字符串函数
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sprintf

(PHP 4, PHP 5)

sprintf — Return a formatted string

说明

string sprintf ( string $format [, mixed $args [, mixed $... ]] )

Returns a string produced according to the formatting string format.

参数

format

The format string is composed of zero or more directives: ordinary characters (excluding %) that are copied directly to the result, and conversion specifications, each of which results in fetching its own parameter. This applies to both sprintf() and printf().

Each conversion specification consists of a percent sign (%), followed by one or more of these elements, in order:

  1. An optional sign specifier that forces a sign (- or +) to be used on a number. By default, only the - sign is used on a number if it's negative. This specifier forces positive numbers to have the + sign attached as well, and was added in PHP 4.3.0.
  2. An optional padding specifier that says what character will be used for padding the results to the right string size. This may be a space character or a 0 (zero character). The default is to pad with spaces. An alternate padding character can be specified by prefixing it with a single quote ('). See the examples below.
  3. An optional alignment specifier that says if the result should be left-justified or right-justified. The default is right-justified; a - character here will make it left-justified.
  4. An optional number, a width specifier that says how many characters (minimum) this conversion should result in.
  5. An optional precision specifier in the form of a period (`.') followed by an optional decimal digit string that says how many decimal digits should be displayed for floating-point numbers. When using this specifier on a string, it acts as a cutoff point, setting a maximum character limit to the string.

  6. A type specifier that says what type the argument data should be treated as. Possible types:

    • % - a literal percent character. No argument is required.
    • b - the argument is treated as an integer, and presented as a binary number.
    • c - the argument is treated as an integer, and presented as the character with that ASCII value.
    • d - the argument is treated as an integer, and presented as a (signed) decimal number.
    • e - the argument is treated as scientific notation (e.g. 1.2e+2). The precision specifier stands for the number of digits after the decimal point since PHP 5.2.1. In earlier versions, it was taken as number of significant digits (one less).
    • E - like %e but uses uppercase letter (e.g. 1.2E+2).
    • u - the argument is treated as an integer, and presented as an unsigned decimal number.
    • f - the argument is treated as a float, and presented as a floating-point number (locale aware).
    • F - the argument is treated as a float, and presented as a floating-point number (non-locale aware). Available since PHP 4.3.10 and PHP 5.0.3.
    • g - shorter of %e and %f.
    • G - shorter of %E and %f.
    • o - the argument is treated as an integer, and presented as an octal number.
    • s - the argument is treated as and presented as a string.
    • x - the argument is treated as an integer and presented as a hexadecimal number (with lowercase letters).
    • X - the argument is treated as an integer and presented as a hexadecimal number (with uppercase letters).

The format string supports argument numbering/swapping. Here is an example:

Example #1 Argument swapping

<?php
$num = 5;
$location = 'tree';

$format = 'There are %d monkeys in the %s';
printf($format, $num, $location);
?>
This will output "There are 5 monkeys in the tree". But imagine we are creating a format string in a separate file, commonly because we would like to internationalize it and we rewrite it as:

Example #2 Argument swapping

<?php
$format = 'The %s contains %d monkeys';
printf($format, $num, $location);
?>
We now have a problem. The order of the placeholders in the format string does not match the order of the arguments in the code. We would like to leave the code as is and simply indicate in the format string which arguments the placeholders refer to. We would write the format string like this instead:

Example #3 Argument swapping

<?php
$format = 'The %2$s contains %1$d monkeys';
printf($format, $num, $location);
?>
An added benefit here is that you can repeat the placeholders without adding more arguments in the code. For example:

Example #4 Argument swapping

<?php
$format = 'The %2$s contains %1$d monkeys.
           That\'s a nice %2$s full of %1$d monkeys.';
printf($format, $num, $location);
?>
When using argument swapping, the n$ position specifier must come immediately after the percent sign (%), before any other specifiers, as shown in the example below.

Example #5 Position specifier with other specifiers

<?php
$format= 'The %2$s contains %1$04d monkeys';
printf($format, $num, $location);
?>

以上例程会输出：

The tree contains 0005 monkeys

args

...

返回值

Returns a string produced according to the formatting string format.

更新日志

版本 说明
4.0.6 Support for argument numbering/swapping was added

范例

Example #6 printf(): various examples

<?php
$n =  43951789;
$u = -43951789;
$c = 65; // ASCII 65 is 'A'

// notice the double %%, this prints a literal '%' character
printf("%%b = '%b'\n", $n); // binary representation
printf("%%c = '%c'\n", $c); // print the ascii character, same as chr() function
printf("%%d = '%d'\n", $n); // standard integer representation
printf("%%e = '%e'\n", $n); // scientific notation
printf("%%u = '%u'\n", $n); // unsigned integer representation of a positive integer
printf("%%u = '%u'\n", $u); // unsigned integer representation of a negative integer
printf("%%f = '%f'\n", $n); // floating point representation
printf("%%o = '%o'\n", $n); // octal representation
printf("%%s = '%s'\n", $n); // string representation
printf("%%x = '%x'\n", $n); // hexadecimal representation (lower-case)
printf("%%X = '%X'\n", $n); // hexadecimal representation (upper-case)

printf("%%+d = '%+d'\n", $n); // sign specifier on a positive integer
printf("%%+d = '%+d'\n", $u); // sign specifier on a negative integer
?>

以上例程会输出：

%b = '10100111101010011010101101'
%c = 'A'
%d = '43951789'
%e = '4.39518e+7'
%u = '43951789'
%u = '4251015507'
%f = '43951789.000000'
%o = '247523255'
%s = '43951789'
%x = '29ea6ad'
%X = '29EA6AD'
%+d = '+43951789'
%+d = '-43951789'

Example #7 printf(): string specifiers

<?php
$s = 'monkey';
$t = 'many monkeys';

printf("[%s]\n",      $s); // standard string output
printf("[%10s]\n",    $s); // right-justification with spaces
printf("[%-10s]\n",   $s); // left-justification with spaces
printf("[%010s]\n",   $s); // zero-padding works on strings too
printf("[%'#10s]\n",  $s); // use the custom padding character '#'
printf("[%10.10s]\n", $t); // left-justification but with a cutoff of 10 characters
?>

以上例程会输出：

[monkey]
[    monkey]
[monkey    ]
[0000monkey]
[####monkey]
[many monke]

Example #8 sprintf(): zero-padded integers

<?php
$isodate = sprintf("%04d-%02d-%02d", $year, $month, $day);
?>

Example #9 sprintf(): formatting currency

<?php
$money1 = 68.75;
$money2 = 54.35;
$money = $money1 + $money2;
// echo $money will output "123.1";
$formatted = sprintf("%01.2f", $money);
// echo $formatted will output "123.10"
?>

Example #10 sprintf(): scientific notation

<?php
$number = 362525200;

echo sprintf("%.3e", $number); // outputs 3.625e+8
?>

参见

字符串函数
在线手册：中文 英文
PHP手册
PHP手册 - N: Return a formatted string

用户评论:

eslindsey at gmail dot com (10-Mar-2012 02:49)

@andrejsstepanovs at gmail dot com:

You should just use PHP's built-in error suppression; that's exactly the kind of situation it's there for:

$str = @sprintf('%s %s %s', 'too few parameters');

krzysiek dot 333 at gmail dot com - zryty dot hekko dot pl (20-Aug-2011 08:48)

Encoding and decoding IP adress to format: 1A2B3C4D (mysql column: char(8) )

<?php
function encode_ip($dotquad_ip)
{
    $ip_sep = explode('.', $dotquad_ip);
    return sprintf('%02x%02x%02x%02x', $ip_sep[0], $ip_sep[1], $ip_sep[2], $ip_sep[3]);
}

function decode_ip($int_ip)
{
    $hexipbang = explode('.', chunk_split($int_ip, 2, '.'));
    return hexdec($hexipbang[0]). '.' . hexdec($hexipbang[1]) . '.' . hexdec($hexipbang[2]) . '.' . hexdec($hexipbang[3]);
}
?>

timo dot frenay at gmail dot com (02-May-2011 01:38)

Here is how to print a floating point number with 16 significant digits regardless of magnitude:

<?php
    $result = sprintf(sprintf('%%.%dF', max(15 - floor(log10($value)), 0)), $value);
?>

This works more reliably than doing something like sprintf('%.15F', $value) as the latter may cut off significant digits for very small numbers, or prints bogus digits (meaning extra digits beyond what can reliably be represented in a floating point number) for very large numbers.

andrejsstepanovs at gmail dot com (21-Apr-2011 03:13)

Use this function to ignore warning "Too few arguments".

<?php
/**
 * Ignores php E_WARNING "sprintf(): Too few arguments".
 * If parameters is too fiew, then this function add extra empty parameter and try again.
 * Working in recursion.
 *
 * @param string $template
 * @param mixed $parameters
 * @return string
 */
function my_sprintf($template, $parameters){
   if(!function_exists('handleError')){//initialize new error handler function
      function handleError($errno, $errstr, $errfile, $errline, array $errcontext){
         throw new ErrorException($errstr, 0, $errno, $errfile, $errline);
      }
      set_error_handler('handleError');
   }

   if(!is_array($parameters)){//manage parameters to allow string
      $parameters = array($parameters);
   }

   try{//trying to execute function. if warning is received, then add parameter
      eval('$return = sprintf($template, "'.implode('","', $parameters).'");');
      return $return;
   }catch(ErrorException $e){
      array_push($parameters, null);
      return my_sprintf($template, $parameters);
   }
}
?>

carmageddon at gmail dot com (02-Feb-2011 02:38)

If you want to convert a decimal (integer) number into constant length binary number in lets say 9 bits, use this:

$binary = sprintf('%08b', $number );

for example:
<?php
$bin = sprintf('%08b',511 );
echo $bin."\n";
?>

would output 111111111
And 2 would output 00000010

I know the leading zeros are useful to me, perhaps they are to someone else too.

dwieeb at gmail dot com (01-Sep-2010 07:54)

If you use the default padding specifier (a space) and then print it to HTML, you will notice that HTML does not display the multiple spaces correctly. This is because any sequence of white-space is treated as a single space.

To overcome this, I wrote a simple function that replaces all the spaces in the string returned by sprintf() with the character entity reference "&nbsp;" to achieve non-breaking space in strings returned by sprintf()

<?php
//Here is the function:
function sprintf_nbsp() {
   $args = func_get_args();
   return str_replace(' ', '&nbsp;', vsprintf(array_shift($args), array_values($args)));
}

//Usage (exactly like sprintf):
$format = 'The %d monkeys are attacking the [%10s]!';
$str = sprintf_nbsp($format, 15, 'zoo');
echo $str;
?>

The above example will output:
The 15 monkeys are attacking the [       zoo]!

<?php
//The variation that prints the string instead of returning it:
function printf_nbsp() {
   $args = func_get_args();
   echo str_replace(' ', '&nbsp;', vsprintf(array_shift($args), array_values($args)));
}
?>

geertdd at gmail dot com (01-Sep-2010 08:53)

Note that when using a sign specifier, the number zero is considered positive and a "+" sign will be prepended to it.

<?php
printf('%+d', 0); // +0
?>

nate at frickenate dot com (14-Nov-2009 07:45)

Here's a clean, working version of functions to allow using named arguments instead of numeric ones. ex: instead of sprintf('%1$s', 'Joe');, we can use sprintf('%name$s', array('name' => 'Joe'));. I've provided 2 different versions: the first uses the php-like syntax (ex: %name$s), while the second uses the python syntax (ex: %(name)s).

<?php

/**
 * version of sprintf for cases where named arguments are desired (php syntax)
 *
 * with sprintf: sprintf('second: %2$s ; first: %1$s', '1st', '2nd');
 *
 * with sprintfn: sprintfn('second: %second$s ; first: %first$s', array(
 *  'first' => '1st',
 *  'second'=> '2nd'
 * ));
 *
 * @param string $format sprintf format string, with any number of named arguments
 * @param array $args array of [ 'arg_name' => 'arg value', ... ] replacements to be made
 * @return string|false result of sprintf call, or bool false on error
 */
function sprintfn ($format, array $args = array()) {
    // map of argument names to their corresponding sprintf numeric argument value
    $arg_nums = array_slice(array_flip(array_keys(array(0 => 0) + $args)), 1);

    // find the next named argument. each search starts at the end of the previous replacement.
    for ($pos = 0; preg_match('/(?<=%)([a-zA-Z_]\w*)(?=\$)/', $format, $match, PREG_OFFSET_CAPTURE, $pos);) {
        $arg_pos = $match[0][1];
        $arg_len = strlen($match[0][0]);
        $arg_key = $match[1][0];

        // programmer did not supply a value for the named argument found in the format string
        if (! array_key_exists($arg_key, $arg_nums)) {
            user_error("sprintfn(): Missing argument '${arg_key}'", E_USER_WARNING);
            return false;
        }

        // replace the named argument with the corresponding numeric one
        $format = substr_replace($format, $replace = $arg_nums[$arg_key], $arg_pos, $arg_len);
        $pos = $arg_pos + strlen($replace); // skip to end of replacement for next iteration
    }

    return vsprintf($format, array_values($args));
}

/**
 * version of sprintf for cases where named arguments are desired (python syntax)
 *
 * with sprintf: sprintf('second: %2$s ; first: %1$s', '1st', '2nd');
 *
 * with sprintfn: sprintfn('second: %(second)s ; first: %(first)s', array(
 *  'first' => '1st',
 *  'second'=> '2nd'
 * ));
 *
 * @param string $format sprintf format string, with any number of named arguments
 * @param array $args array of [ 'arg_name' => 'arg value', ... ] replacements to be made
 * @return string|false result of sprintf call, or bool false on error
 */
function sprintfn ($format, array $args = array()) {
    // map of argument names to their corresponding sprintf numeric argument value
    $arg_nums = array_slice(array_flip(array_keys(array(0 => 0) + $args)), 1);

    // find the next named argument. each search starts at the end of the previous replacement.
    for ($pos = 0; preg_match('/(?<=%)\(([a-zA-Z_]\w*)\)/', $format, $match, PREG_OFFSET_CAPTURE, $pos);) {
        $arg_pos = $match[0][1];
        $arg_len = strlen($match[0][0]);
        $arg_key = $match[1][0];

        // programmer did not supply a value for the named argument found in the format string
        if (! array_key_exists($arg_key, $arg_nums)) {
            user_error("sprintfn(): Missing argument '${arg_key}'", E_USER_WARNING);
            return false;
        }

        // replace the named argument with the corresponding numeric one
        $format = substr_replace($format, $replace = $arg_nums[$arg_key] . '$', $arg_pos, $arg_len);
        $pos = $arg_pos + strlen($replace); // skip to end of replacement for next iteration
    }

    return vsprintf($format, array_values($args));
}

?>

Astone (16-Sep-2009 07:41)

When you're using Google translator, you have to 'escape' the 'conversion specifications' by putting <span class="notranslate"></span> around them.

Like this:

<?php

function getGoogleTranslation($sString, $bEscapeParams = true)
{
    // "escape" sprintf paramerters
    if ($bEscapeParams)
    {
        $sPatern = '/(?:%%|%(?:[0-9]+\$)?[+-]?(?:[ 0]|\'.)?-?[0-9]*(?:\.[0-9]+)?[bcdeufFosxX])/';       
        $sEscapeString = '<span class="notranslate">$0</span>';
        $sString = preg_replace($sPatern, $sEscapeString, $sString);
    }

    // Compose data array (English to Dutch)
    $aData = array(
        'v'            => '1.0',
        'q'            => $sString,
        'langpair'    => 'en|nl',
    );

    // Initialize connection
    $rService = curl_init();
   
    // Connection settings
    curl_setopt($rService, CURLOPT_URL, 'http://ajax.googleapis.com/ajax/services/language/translate');
    curl_setopt($rService, CURLOPT_RETURNTRANSFER, true);
    curl_setopt($rService, CURLOPT_POSTFIELDS, $aData);
   
    // Execute request
    $sResponse = curl_exec($rService);

    // Close connection
    curl_close($rService);
   
    // Extract text from JSON response
    $oResponse = json_decode($sResponse);
    if (isset($oResponse->responseData->translatedText))
    {
        $sTranslation = $oResponse->responseData->translatedText;
    }
    else
    {
        // If some error occured, use the original string
        $sTranslation = $sString;
    }
   
    // Replace "notranslate" tags
    if ($bEscapeParams)
    {
        $sEscapePatern = '/<span class="notranslate">([^<]*)<\/span>/';
        $sTranslation = preg_replace($sEscapePatern, '$1', $sTranslation);
    }
   
    // Return result
    return $sTranslation;
}

?>

Thanks to MelTraX for defining the RegExp!

Jay Gilford (26-Aug-2009 01:13)

I created this function a while back to save on having to combine mysql_real_escape_string onto all the params passed into a sprintf. it works literally the same as the sprintf other than that it doesn't require you to escape your inputs. Hope its of some use to people

<?php
function mressf()
{
    $args = func_get_args();
    if (count($args) < 2)
        return false;
    $query = array_shift($args);
    $args = array_map('mysql_real_escape_string', $args);
    array_unshift($args, $query);
    $query = call_user_func_array('sprintf', $args);
    return $query;
}
?>

Regards
Jay
Jaygilford.com

jfgrissom at gmail dot com (12-Jul-2009 05:51)

I had a nightmare trying to find the two's complement of a 32 bit number.

I got this from http://www.webmasterworld.com/forum88/13334.htm (credit where credit is due... =P  )

Quote: ...find out the 2's complement of any number, which is -(pow(2, n) - N) where n is the number of bits and N is the number for which to find out its 2's complement.

This worked magic for me... previously I was trying to use

sprintf ("%b",$32BitDecimal);
But it always returned 10000000000000000000000 when the $32BitDecimal value got above 2,000,000,000.

This -(pow(2, n) - N)
Worked remarkably well and was very accurate.

Hope this helps someone fighting with two's complement in PHP.

John Walker (10-Jul-2009 01:56)

To add to other notes below about floating point problems, I noted that %f and %F will apparently output a maximum precision of 6 as a default so you have to specify 1.15f (eg) if you need more.

In my case, the input (from MySQL) was a string with 15 digits of precision that was displayed with 6. Likely what happens is that the rounding occurs in the conversion to a float before it is displayed. Displaying it as 1.15f (or in my case, %s) shows the correct number.

viktor at textalk dot com (18-Feb-2009 04:16)

A more complete and working version of mb_sprintf and mb_vsprintf. It should work with any "ASCII preserving" encoding such as UTF-8 and all the ISO-8859 charsets. It handles sign, padding, alignment, width and precision. Argument swapping is not handled.

<?php
if (!function_exists('mb_sprintf')) {
  function mb_sprintf($format) {
      $argv = func_get_args() ;
      array_shift($argv) ;
      return mb_vsprintf($format, $argv) ;
  }
}
if (!function_exists('mb_vsprintf')) {
  /**
   * Works with all encodings in format and arguments.
   * Supported: Sign, padding, alignment, width and precision.
   * Not supported: Argument swapping.
   */
  function mb_vsprintf($format, $argv, $encoding=null) {
      if (is_null($encoding))
          $encoding = mb_internal_encoding();

      // Use UTF-8 in the format so we can use the u flag in preg_split
      $format = mb_convert_encoding($format, 'UTF-8', $encoding);

      $newformat = ""; // build a new format in UTF-8
      $newargv = array(); // unhandled args in unchanged encoding

      while ($format !== "") {
     
        // Split the format in two parts: $pre and $post by the first %-directive
        // We get also the matched groups
        list ($pre, $sign, $filler, $align, $size, $precision, $type, $post) =
            preg_split("!\%(\+?)('.|[0 ]|)(-?)([1-9][0-9]*|)(\.[1-9][0-9]*|)([%a-zA-Z])!u",
                       $format, 2, PREG_SPLIT_DELIM_CAPTURE) ;

        $newformat .= mb_convert_encoding($pre, $encoding, 'UTF-8');
       
        if ($type == '') {
          // didn't match. do nothing. this is the last iteration.
        }
        elseif ($type == '%') {
          // an escaped %
          $newformat .= '%%';
        }
        elseif ($type == 's') {
          $arg = array_shift($argv);
          $arg = mb_convert_encoding($arg, 'UTF-8', $encoding);
          $padding_pre = '';
          $padding_post = '';
         
          // truncate $arg
          if ($precision !== '') {
            $precision = intval(substr($precision,1));
            if ($precision > 0 && mb_strlen($arg,$encoding) > $precision)
              $arg = mb_substr($precision,0,$precision,$encoding);
          }
         
          // define padding
          if ($size > 0) {
            $arglen = mb_strlen($arg, $encoding);
            if ($arglen < $size) {
              if($filler==='')
                  $filler = ' ';
              if ($align == '-')
                  $padding_post = str_repeat($filler, $size - $arglen);
              else
                  $padding_pre = str_repeat($filler, $size - $arglen);
            }
          }
         
          // escape % and pass it forward
          $newformat .= $padding_pre . str_replace('%', '%%', $arg) . $padding_post;
        }
        else {
          // another type, pass forward
          $newformat .= "%$sign$filler$align$size$precision$type";
          $newargv[] = array_shift($argv);
        }
        $format = strval($post);
      }
      // Convert new format back from UTF-8 to the original encoding
      $newformat = mb_convert_encoding($newformat, $encoding, 'UTF-8');
      return vsprintf($newformat, $newargv);
  }
}
?>

splogamurugan at gmail dot com (06-Feb-2009 01:59)

$format = 'There are %1$d monkeys in the %s and %s ';
printf($format, 100, 'Chennai', 'Bangalore');

Expecting to output
"There are 100 monkeys in the Chennai and bangalore"

But, this will output
"There are 100 monkeys in the 100 and Chennai"

Because, the second and Third specifiers takes 1rst and 2nd arguments. Because it is not assigned with any arguments.

remy dot damour at -please-no-spam-laposte dot net (15-Jan-2009 07:15)

With printf() and sprintf() functions, escape character is not backslash '\' but rather '%'.

Ie. to print '%' character you need to escape it with itself:
<?php
printf('%%%s%%', 'koko'); #output: '%koko%'
?>

MelTraX (05-Nov-2008 09:40)

<?php
  // parses a string meant for printf and returns an array of found parameters (or NULL if it contains syntax errors)
  function parsePrintfParameters($string) {
    $valid = '/^(?:%%|%(?:[0-9]+\$)?[+-]?(?:[ 0]|\'.)?-?[0-9]*(?:\.[0-9]+)?[bcdeufFosxX])/';
    $originalString = $string;

    $result = array();
    while(strlen($string)) {
      if(!$string = preg_replace('/^[^%]*/', '', $string))
        break;

      if(preg_match($valid, $string, $matches)) {
        $result[] = $matches[0];
        $string = substr($string, strlen($matches[0]));
      } else {
        error(sprintf('"%s" has an error near "%s".', $originalString, $string));
        return NULL;
      }
    }
    return $result;
  }
?>

savannah at seznam dot cz (12-Oct-2008 12:29)

If you have problems using utf-8 with string paddings, you can use this function:

<?php
/**
 * Formats string using sprintf, but correctly handles %s  with space paddings
 *
 * uses conversion to iso-8859-2 and back
 *
 * it is, however, much slower, so use only when needed!
 *
 * @param string $format
 */
function utf_8_sprintf ($format) {
  $args = func_get_args();

  for ($i = 1; $i < count($args); $i++) {
    $args [$i] = iconv('UTF-8', 'ISO-8859-2', $args [$i]);
  }
 
  return iconv('ISO-8859-2', 'UTF-8', call_user_func_array('sprintf', $args));
}

// test

echo sprintf ("[%-20s]\n", 'escrzyaie'); //  how it should look without special chars
echo sprintf ("[%-20s]\n", 'ě?????áíé'); // not correctly handled by php
echo utf_8_sprintf ("[%-20s]\n", 'ě?????áíé'); // using above function

/*
produces:
[escrzyaie           ]
[ě?????áíé  ]
[ě?????áíé           ]
*/

?>
the trick is to convert arguments to iso8859-2 and result back to utf-8.

php at mikeboers dot com (01-Oct-2008 09:42)

And continuing on the same theme of a key-based sprintf...

I'm roughly (I can see a couple cases where it comes out wierd) copying the syntax of Python's string formatting with a dictionary. The improvement over the several past attempts is that this one still respects all of the formating options, as you can see in my example.

And the error handling is really crappy (just an echo). I just threw this together so do with it what you will. =]

<?php

function sprintf_array($string, $array)
{
    $keys    = array_keys($array);
    $keysmap = array_flip($keys);
    $values  = array_values($array);
   
    while (preg_match('/%\(([a-zA-Z0-9_ -]+)\)/', $string, $m))
    {   
        if (!isset($keysmap[$m[1]]))
        {
            echo "No key $m[1]\n";
            return false;
        }
       
        $string = str_replace($m[0], '%' . ($keysmap[$m[1]] + 1) . '$', $string);
    }
   
    array_unshift($values, $string);
    var_dump($values);
    return call_user_func_array('sprintf', $values);
}

echo sprintf_array('4 digit padded number: %(num)04d ', array('num' => 42));

?>

Cheers!

ant at loadtrax dot com (18-Jun-2008 10:19)

Rounding seems a little inconsistent, so beware:

$ php -a

php> print round(1.0*20*1.175/100,2);
0.24
php > print sprintf("%.2f",1.0*20*1.175/100);
0.23
php > print sprintf("%.0f",1.0*20*1.175);
24

I get round this by doing the round first, then doing the sprintf.

jaimthorn at yahoo dot com (11-Jun-2008 03:01)

I needed a piece of code similar to the one Matt posted below, on the 10th of March, 2008.  However, I wasn't completely satisfied with Matt's code (sorry, Matt!  No offense intended!), because

1) I don't like to initialize variables when it's not really needed, and
2) it contains two bugs.

What are the bugs?

First, Matt's code tests for count($vars) > 0, but if $var == "Hello world!", then count($var) == 1, but the foreach() will crash because $var has to be an array.  So instead, my code tests for is_array($var).

Second, if a key in $vars is a prefix of any of the later keys in the array (like 'object' is the beginning of 'objective') then the str_replace messes things up.  This is no big deal if your keys are hard-coded and you can make sure the keys don't interfere, but in my code the keys are variable.  So I decided to first sort the array on a decreasing length of the key.

<?php

function cmp($a, $b)
{
    return strlen($b) - strlen($a);
}

function sprintf2($str, $vars, $char = '%')
{
    if(is_array($vars))
    {
        uksort($vars, "cmp");

        foreach($vars as $k => $v)
        {
            $str = str_replace($char . $k, $v, $str);
        }
    }

    return $str;
}

echo sprintf2( 'Hello %your_name, my name is %my_name! I am %my_age, how old are you? I like %object and I want to %objective_in_life!'
             , array( 'your_name'         => 'Matt'
                    , 'my_name'           => 'Jim'
                    , 'my_age'            => 'old'
                    , 'object'            => 'women'
                    , 'objective_in_life' => 'write code'
                    )
             );

?>

If possible, and if you're willing, you can also embed the key fields in the text between percent-signs, rather than prefixing the keys with one.  Sorting is no longer necessary, and the execution time is less than half of the code above:

<?php

function sprintf3($str, $vars, $char = '%')
{
    $tmp = array();
    foreach($vars as $k => $v)
    {
        $tmp[$char . $k . $char] = $v;
    }
    return str_replace(array_keys($tmp), array_values($tmp), $str);
}

echo sprintf3( 'Hello %your_name%, my name is %my_name%! I am %my_age%, how old are you? I like %object% and I want to %objective_in_life%!'
             , array( 'your_name'         => 'Matt'
                    , 'my_name'           => 'Jim'
                    , 'my_age'            => 'old'
                    , 'object'            => 'women'
                    , 'objective_in_life' => 'write code'
                    )
             );
?>

If you're willing to embed the keys in the text, you may also be willing to embed the keys themselves in percent signs, thus shaving off another 30% of the execution time:

<?php

function sprintf4($str, $vars)
{
    return str_replace(array_keys($vars), array_values($vars), $str);
}

echo sprintf4( 'Hello %your_name%, my name is %my_name%! I am %my_age%, how old are you? I like %object% and I want to %objective_in_life%!'
             , array( '%your_name%'         => 'Matt'
                    , '%my_name%'           => 'Jim'
                    , '%my_age%'            => 'old'
                    , '%object%'            => 'women'
                    , '%objective_in_life%' => 'write code'
                    )
             );
?>

Of course, by now the sprintf function is no longer something you'd want to write to mum and dad about...

ranema at ubuntu dot polarhome dot com (30-Mar-2008 03:40)

It's very comfortible for long Sql queries:

<?php
$_gQuery = "UPDATE `x` SET `a` = %i AND `b` = '%s' WHERE `my` = '%s';"; // ........

mysql_query( sprintf( $_gQuery, 10, 'a', 'rrrr' ) );
?>

But if you have a short query, then it would be much faster to append your data by using `.`.

<?php
$_gQuery = 'SELECT COUNT(*) FROM `' . $_gName . '`;';
?>

matt (10-Mar-2008 05:13)

Was looking for a assoc way of using sprintf but couldnt find one, probably wasnt looking hard enough so came up with this. Very very simple indeed...

<?php

function sprintf2($str='', $vars=array(), $char='%')
{
    if (!$str) return '';
    if (count($vars) > 0)
    {
        foreach ($vars as $k => $v)
        {
            $str = str_replace($char . $k, $v, $str);
        }
    }

    return $str;
}

echo sprintf2('Hello %your_name my name is %my_name! I am %my_age, how old are you? I like %object!', array(
    'your_name' => 'Ben',
    'my_name' => 'Matt',
    'my_age' => '21',
    'object' => 'food'
));

// Hello Ben my name is Matt! I am 21, how old are you? I like food!

?>

Looks nice anyway :)

andyhaslam at hotmail dot com (05-Feb-2008 05:46)

An interesting bug, if you do the following:

$val = 2345.35;
$val = sprintf("%01.2f", $val);
echo $val;

Output is "2.00", instead of "2345.35". The solution is to use an intermediate variable:

$val = 2345.35;
$val2 = sprintf("%01.2f", $val);
$val = $val2;
echo $val;

scott dot gardner at mac dot com (10-Jan-2008 09:22)

In the last example of Example#6, there is an error regarding the output.

printf("[%10.10s]\n", $t); // left-justification but with a cutoff of 10 characters

This outputs right-justified.

In order to output left-justified:

printf("[%-10.10s]\n", $t);

me at umarfarooq dot net (07-Sep-2007 07:29)

/**
This function returns a formated  string with the legnth you specify
@string holds the string which you want to format
@len holds the length you want to format
**/
function formatString($string, $len)
{
    if (strlen($string) < $len)
    {
        $addchar=($len - strlen($string)) ;
        for ($i = 0; $i < $addchar; $i++)
        {
            $string=sprintf("$string%s", "0");
        }
    }
   
    if (strlen($string) > $len)
    {
        $string=substr($string,0,$len);
    }
   
    return $string;   
}

Thomas Breuss (11-May-2007 08:03)

Note:
If you want to use % in sprintf, you have to "quote" it like %%.

Example:
echo sprintf("Green => %d%%'", 50);

Output:
Green => 50%

eagle at electric-force dot net (28-Mar-2007 07:25)

Display an binary string like an Hex Editor.

<?php
function BinToHexView($binstr) {
    $HexView = "";

    $binpos = 0;
    $binsize = strlen($binstr);
    $binr = ( ($binsize-$binpos-16) > 16 ? 16 : $binsize-$binpos-16 );

    while ($binr > 0) {
        $hline = "";
        $dline = "";
        $HexView .= sprintf("%04x", $binpos);
        for ($c=0;$c<$binr;$c++) {
            $hline .= sprintf("%02x",ord($binstr[$binpos+$c]))." ";
        }
        for ($c=0;$c<$binr;$c++) {
            $ord = ord($binstr[$binpos+$c]);
            $dline .= ( $ord<32 || $ord>126 ? "." : $binstr[$binpos+$c] );
        }
        $HexView .= sprintf("  %-48s  %-16s\n", $hline, $dline);
        $binpos += $binr;
        $binr = ( ($binsize-$binpos-16) > 16 ? 16 : $binsize-$binpos-16 );
    }

    return $HexView;
}
?>

(29-Jan-2007 06:15)

In response to juan at ecogomera dot com:

I think what you want is:

$x = 3327
$y=decbin($x);
echo $y."<br>";
$z = sprintf("%012d", $x);
echo $z;

3327
110011111111
000000003327

Right? You were double-converting the number. First to binary, then again to decimal. You should be converting the source number directly into the required base.

SWestrup (09-Nov-2006 07:46)

In response to Anonymous, who claimed that:

  printf("[%s]\n", str_pad('Hello', 20));

and

  printf("[%-20s]\n", 'Hello');

are the same thing: you've missed the point.

They're only the same when the amount of padding is a known constant. When its a variable (or an expression), its often much more convenient to be able to write:

  printf("[%-*s]\n", 3*$n+2, "Hello");

than what you have to go through now, which is either:

  $t = 3*$n+2;
  printf("[%-{$t}s]\n","Hello");

or

  printf("[%s]\n", str_pad('Hello', 3*$n+2));

Anonymous (17-Oct-2006 12:04)

In response to Fredrik Rambris in the com top domain:

<?php

//Your code:

printf("[%s]\n", str_pad('Hello', 20));

//Is the same as:

printf("[%-20s]\n", 'Hello');

?>

Fredrik Rambris in the com top domain (28-Sep-2006 10:48)

The C implementation of printf (alteast in glibc) can handle field length as arguments like this:

printf("[%-*s]\n", (int)20, "Hello");

To have the same result in PHP you need to run

printf("[%s]\n, str_pad("Hello", 20) );

It would be nice if one could use the field length directly like in C.

Moore (at) Hs-Furtwangen (dot) De (12-Aug-2006 07:54)

Here a litle function that might come handy one time:
It gives back a String and adds a <BR> (you can change it to <br />) to every line end. And it adds $num blanks to the front of the next line.

<?php
 function nl2brnl($text, $num)
  {
   return preg_replace("/\\r\\n|\\n|\\r/", sprintf("% -".(5+$num)."s","<BR>\\n"), $text);
  }

$a = " one\\n two\\r\\n three";

$b = nl2brnl($a, 2);

var_dump($b);

/* output will be:
string(30) " one<BR>
   two<BR>
   three"
*/

echo "  <P>\\n   ";
echo $b

/* output will be:
  <P>
   one<BR>
   two<BR>
   three
*/
?>
Is helpfull for avouding code_soup.

bknakkerNO at SPAMgmail dot com (10-Aug-2006 10:54)

Note that in PHP5 (.1.4 for me) sprintf will not use the __toString function of an object.

<?php
class pr{
private $l;
public function __construct($l)
{
$this->l=$l;
}
public function __toString()
{
return $this->l;
}
}
echo new pr('This works!!'); //This will display 'This works!!'
echo sprintf(new pr('This doesnt')); // will display 'Object'
?>

Be careful with that!

Ulf Wostner (06-Aug-2006 06:35)

<?php
#-----------------------------------------------------
# Viewing Two's Complement using sprintf formatting.
#-----------------------------------------------------
# Systems using Two's Complements have exactly one number that equals its own Two's Complement.
# On a 32-bit system look at  1000 0000 0000 0000  for  -2147483648
# Take the one's complement, to get 0111 1111 1111 1111, add 1
# to get the Two's Complement: 1000 0000 0000 0000
#  We are back to the original number, the so-called Weird Number for 32-bits.

# For a 64-bit system, format that number as binary, width 64, padded with 0's.

printf("%064b\n", -2147483648);

# Output with added spaces:
# 11111111 11111111 11111111 11111111 10000000 00000000 00000000 00000000

# And here is the Two's Complement on a 64-bit system.

printf("%064b\n", +2147483648);

# Output with added spaces:
# 00000000 00000000 00000000 00000000 10000000 00000000 00000000 00000000
# They share those last 32 bits, accounting for the 32-bit Weird Number.

#----------------------------------------------------------
# Is PHP running  32-bit or 64-bit?
#----------------------------------------------------------
# Sure, we can look at the max int, but  The Weird Number  also tells if we are in 32-bit, 64-bit, or ...

function getBitCount() {
  $how_many_bits = 1;  $n = 2;
  while(True) {
    $how_many_bits += 1;   $n *= 2;  # powers of 2
    # matches its own two's complement? 
    if( sprintf("%b", $n) == sprintf("%b", -$n)  )
      return 1 + $how_many_bits;
  }
  return;
}
?>

egingell at sisna dot com (26-Apr-2006 09:51)

<?
/**
 * [string or int] vprint ( string $format [, mixed $ary [, bool $return]] )
 *
 * Closely mimics the functionality of sprintf(), printf(), vprintf(), and vsprintf().
 *
 * Replaces %[bcdeufFosxX] with each element of $ary
 *     See http://us3.php.net/manual/en/function.sprintf.php for details on replacement types.
 *
 * If there are not enough elements in $ary (or it is left out) to satisfy $format,
 *     it will be padded to the correct length.
 *
 * Since v*printf() doesn't mind having too many elements in the array, $format will be left alone.
 *
 * If $ary is a string, it will be recast into an array.
 *
 * If $return is set to a value considered to be false (0, '', null, false, and array()),
 *     then the output will be sent to STDOUT and the strlen() of the output string will be returned;
 *     otherwise, the output string will be returned.
 *
 * It's buggy when using the argument swapping functionality, unless you do it propperly.
 *
 * May break when using modifiers (%.4e, %02s, etc), unless you do it propperly.
 **/
function vprint($format, $ary = array(), $return = true) {
    // Sanity?!
    if (!is_array($ary)) $ary = array($ary);

    // Find %n$n.
    preg_match_all('#\\%[\\d]*\\$[bcdeufFosxX]#', $format, $matches);

    // Weed out the dupes and count how many there are.
    $counts = count(array_unique($matches[0]));

    // Count the number of %n's and add it to the number of %n$n's.
    $countf = preg_match_all('#\\%[bcdeufFosxX]#', $format, $matches) + $counts;

    // Count the number of replacements.
    $counta = count($ary);

    if ($countf > $counta) {
        // Pad $ary if there's not enough elements.
        $ary = array_pad($ary, $countf, "&nbsp;");
    }

    if ($return) {
        return vsprintf($format, $ary);
    } else {
        return vprintf($format, $ary);
    }
}

?>

mauf at franzoni dot info (16-Feb-2006 03:21)

The format of floating values has been previously reporting as depending on platform (linux / windows) yet I see it changes within two linux systems depending on the version:
In V4.2.2 "%3.2" displays 3 integers and two decimals (i.e. the first digit represents just the number of integer digits), on V4.4.1 the same displays (and justifies the string to) a three character string (i.e. the first digit is the total lenght of the number, including the decimal dot).

Maybe someone may better specify which version this happens from.

darkfalconIV at hotmail dot com (18-Dec-2005 08:57)

henke dot andersson

You can accomplish feeding it array if you use call_user_func_array. Not exactly a `clean' option, but it does work.

tim dot brouckaert dot NOSPAM at gmail dot com (12-Oct-2005 01:35)

If you want to center align some text using the printf or sprintf functions, you can just use the following:

function center_text($word){
    $tot_width = 30;
    $symbol = "-";
    $middle = round($tot_width/2);
    $length_word = strlen($word);
    $middle_word = round($length_word / 2);
    $last_position = $middle + $middle_word;
    $number_of_spaces = $middle - $middle_word;

    $result = sprintf("%'{$symbol}{$last_position}s", $word);
        for ($i = 0; $i < $number_of_spaces; $i++){
            $result .= "$symbol";
        }
    return $result;
}

$string = "This is some text";
print center_text($string);

off course you can modify the function to use more arguments.

webmaster at cafe-clope dot net (15-Aug-2005 05:47)

trying to fix the multibyte non-compliance of sprintf, I came to that :

<?php
function mb_sprintf($format) {
    $argv = func_get_args() ;
    array_shift($argv) ;
    return mb_vsprintf($format, $argv) ;
}

function mb_vsprintf($format, $argv) {
    $newargv = array() ;
   
    preg_match_all("`\%('.+|[0 ]|)([1-9][0-9]*|)s`U", $format, $results, PREG_SET_ORDER) ;
   
    foreach($results as $result) {
        list($string_format, $filler, $size) = $result ;
        if(strlen($filler)>1)
            $filler = substr($filler, 1) ;
        while(!is_string($arg = array_shift($argv)))
            $newargv[] = $arg ;
        $pos = strpos($format, $string_format) ;
        $format = substr($format, 0, $pos)
                  . ($size ? str_repeat($filler, $size-strlen($arg)) : '')
                    . str_replace('%', '%%', $arg)
                    . substr($format, $pos+strlen($string_format))
                    ;
    }
       
    return vsprintf($format, $newargv) ;
}

?>

handle with care :
1. that function was designed mostly for utf-8. i guess it won't work with any static mb encoding.
2. my configuration sets the mbstring.func_overload configuration directive to 7, so you may wish to replace substr, strlen, etc. with mb_* equivalents.
3. since preg_* doesn't complies with mb strings, I used a '.+' in the regexp to symbolize an escaped filler character. That means, %'xy5s pattern will match, unfortunately. It is recomended to remove the '+', unless you are intending to use an mb char as filler.
4. the filler fills at left, and only at left.
5. I couldn't succeed with a preg_replace thing : the problem was to use the differents lengths of the string arguements in the same replacement, string or callback. That's why the code is much longuer than I expected.
6. The pattern wil not match any %1\$s thing... just was too complicated for me.
7. Although it has been tested, and works fine within the limits above, this is much more a draft than a end-user function. I would enjoy any improvment.

The test code below shows possibilities, and explains the problem that occures with an mb string argument in sprintf.

<?php
header("content-type:text/plain; charset=UTF-8") ;
$mb_string = "xxx" ;
echo sprintf("%010s", $mb_string), " [octet-size: ", str_sizeof($mb_string) , " ; count: ", strlen(sprintf("%010s", $mb_string)), " characters]\n" ;
echo mb_sprintf("%010s", $mb_string), " [octet-size: ", str_sizeof($mb_string) , " ; count: ", strlen(mb_sprintf("%010s", $mb_string)), " characters]\n" ;
echo "\n" ;
echo mb_sprintf("%''10s\n%'010s\n%'10s\n%10d\n%'x10s\n%010s\n% 10s\n%010s\n%'1s\n", "zero", "one", "two", 3, "four", "ve", "%s%i%x", "ve", "eight") ;
?>

david at rayninfo dot co dot uk (17-Jun-2005 07:33)

Using sprintf to force leading leading zeros

foreach (range(1, 10) as $v) {echo "<br>tag_".sprintf("%02d",$v);}

displays
tag_01
tag_02
tag_03
.. etc

ian dot w dot davis at gmail dot com (30-May-2005 03:03)

Just to elaborate on downright's point about different meanings for %f, it appears the behavior changed significantly as of 4.3.7, rather than just being different on different platforms. Previously, the width specifier gave the number of characters allowed BEFORE the decimal. Now, the width specifier gives the TOTAL number of characters. (This is in line with the semantics of printf() in other languages.) See bugs #28633 and #29286 for more details.

Pacogliss (02-May-2005 08:08)

Just a reminder for beginners : example 6 'printf("[%10s]\n",    $s);' only works (that is, shows out the spaces) if you put the html '<pre></pre>' tags ( head-scraping time saver ;-).

christian at wenz dot org (18-Apr-2005 08:20)

@ henke dot andersson at comhem dot se: Use vprintf()/vsprintf() for that.

henke dot andersson at comhem dot se (15-Apr-2005 04:07)

Mind that it doesn't allow you to use a array as multiple arguments like this:
<?php
printf('%s %s',array('a','b')) ?>

downright at comcast dot net (31-Jan-2005 10:03)

Just thought I'd give a heads up for anyone doing cross platform applications.

sprintf spacing is different numerically with Windows and Linux.

Linux aligned correctly:
$ol = sprintf ("%-6s|%11.2f|%11.2f|%11.2f|%11.2f|%11.2f|%11.2f|%11.2f|%11.2f\n",

Windows aligned correctly:
$ol = sprintf ("%-6s|%14.2f|%14.2f|%14.2f|%14.2f|%14.2f|%14.2f|%14.2f|%14.2f\n",

As you can see the strings are fine for spacing, however, the numbers need a difference of 3 in order to have the same amount of spaces.

I noticed this after using sprintf to format a header for a web app I was working on.  On windows it fit, however, when it came to linux it was MUCH larger than the header.

jrpozo at conclase dot net (21-Jan-2005 03:13)

Be careful if you use the %f modifier to round decimal numbers as it (starting from 4.3.10) will no longer produce a float number if you set certain locales, so you can't accumulate the result. For example:

setlocale(LC_ALL, 'es_ES');
echo(sprintf("%.2f", 13.332) + sprintf("%.2f", 14.446))

gives 27 instead of 27.78, so use %F instead.

timo at frenay dot net (10-Jan-2005 06:58)

Note that the documentation is unclear about the details of the sign specifier. First of all, the character for this is "+".

Also note that the following does NOT print "+00.00" as you might expect:

<?php
    printf('%+02.2f', 0);
?>

The sign is included in the width. This can't be solved by increasing the width:

<?php
    printf('%+03.2f', 0);
?>

This will put the padding 0 before the sign.
Here is a possible solution:

<?php
    $value = 0;
    printf('%s%02.2f', ($value < 0) ? '-' : '+', abs($value));
?>

Gkeeper80 (11-Aug-2004 11:58)

When using sprintf with padding, it's important to note that specifying the length of your padding does not restrict the length of your output.

For example:
$var = 'test';
$output sprintf("%03s", $var);

print $output;

Produces:
test

NOT:
est

This may seem intuitive for working with numbers, but not neccesarily when working with strings.

rex (15-Jun-2004 10:47)

Note, if you are just looking for something to pad out a string consider str_pad.

From testing, it seems faster and was more intuitive to use (for example, making it pad the begining or end of a string... with sprintf you would have to use negative indexes)

php at sharpdreams dot com (08-May-2004 10:13)

Note that when using the argument swapping, you MUST number every argument, otherwise sprintf gets confused. This only happens if you use number arguments first, then switch to a non-numbered, and then back to a numbered one.

<?php
$sql = sprintf( "select * from %1\$s left join %2\$s on( %1\$s.id = %2\$s.midpoint ) where %1\$s.name like '%%%s%%' and %2\$s.tagname is not null", "table1", "table2", "bob" );
// Wont work:
// Sprintf will complain about not enough arguments.
$sql = sprintf( "select * from %1\$s left join %2\$s on( %1\$s.id = %2\$s.midpoint ) where %1\$s.name like '%%%3\$s%%' and %2\$s.tagname is not null", "table1", "table2", "bob" );
// Will work: note the %3\$s
?>

tobias at silverxnet dot de (17-Apr-2004 03:09)

Regarding the previous posting:
I just wanted to give an explanation. This should be because the float to string / integer to string conversion (you are using a string, multiplying it with a float value what php automatically causes to convert the string to a float value). This is a general "problem" (or not), but not that hard to explain.
Where an integer or float starts with 0, in a string it does obviously with 1. So if you are using a string your value will increase by one (You started with a string, so it does not increase but contain the real result. If you start using a float value by not using '' around the value, you have to output the float value as well. This is just the PHP conversion.)

Try putting
$x = strval( $x );
after
$x = $x * 100;
and using your example again. You will see that the output will change to 13664 = 13664 because of the general string conversion. It seems that PHP is converting a float to a string by inceasing by one. By doing the same with intval instead of strval the output changes to 13663 = 13663.

! sprintf seems to behave wrong when using the conversation to an integer value and NOT doing the conversation at all. So use intval to convert to an integer value or strval to convert to a string value BEFORE using sprintf. This should be solving the problems.

kekec at kukac dot hu (29-Mar-2004 05:16)

A really working one:
<?php
function cutzero($value) {
   return preg_replace("/(\.?)0+$/", "", $value);
}
?>

(05-Mar-2004 06:54)

both of your cut-zero functions are just way too complicated. if it's a string where only the zeros at the end should be truncated, why not use a syntax as simple as rtrim("4.7000","0") ?

Rene dot Leonhardt at agritec24 dot com (16-May-2003 06:02)

Your cutzero function could be faster ;-)
   return (double)$value;

But if you must have a function:
   return preg_replace('/0+$/', '', $value);

kouber at php dot net (08-May-2003 10:55)

If you want to cut all the zeros off the end of a float, but not losing any sensitive information, use this:

<?
function cutzero($value) {
    return preg_replace("/(\.\d+?)0+$/", "$1", $value)*1;
}
?>

Some examples:

<?
cutzero("4.7600");     // returns 4.76
cutzero("4.7604")      // returns 4.7604
cutzero("4.7000");     // returns 4.7
cutzero("4.0000");     // returns 4
?>

info at nospam dot webtip dot dk (18-Feb-2003 01:06)

If you want to format a phonenumber with spaces, use chunk_split() which splits a string into smaller chunks. It's much simpler than using sprintf.

$phone = "12345678";

chunk_split ($phone, 2);

will return 12 34 56 78

moritz dot geselle at invision-team dot de (02-Dec-2002 10:52)

a little note to the argument swapping examples which took me a while to get:
if you use single quotes for the format string (like you should do, since there aren't any variable conversions to do as long as you don't need any special chars), the given examples won't work because of the backslash before the $ (needs to be escaped in double quoted strings - but not in single quoted!)

so this:

$format = "The %2\$s contains %1\$d monkeys";
printf($format,$num,$location);

with a single quoted format string would look like this:

$format = 'The %2$s contains %1$d monkeys';
printf($format,$num,$location);

(no escapes)

I hope that helps to avoid confusion ;)

no dot email dot address at example dot com (16-Sep-2002 02:29)

Using argument swapping in sprintf() with gettext: Let's say you've written the following script:

<?php
$var = sprintf(gettext("The %2\$s contains %1\$d monkeys"), 2, "cage");
?>

Now you run xgettext in order to generate a .po file. The .po file will then look like this:

#: file.php:9
#, ycp-format
msgid "The %2\\$s contains %1\\$d monkeys"
msgstr ""

Notice how an extra backslash has been added by xgettext.

Once you've translated the string, you must remove all backslashes from the ID string as well as the translation, so the po file will look like this:

#: file.php:9
#, ycp-format
msgid "The %2$s contains %1$d monkeys"
msgstr "Der er %1$d aber i %2$s"

Now run msgfmt to generate the .mo file, restart Apache to remove the gettext cache if necessary, and you're off.

abiltcliffe at bigfoot.com (10-Sep-2002 07:01)

To jrust at rustyparts.com, note that if you're using a double-quoted string and *don't* escape the dollar sign with a backslash, $s and $d will be interpreted as variable references. The backslash isn't part of the format specifier itself but you do need to include it when you write the format string (unless you use single quotes).

Andrew dot Wright at spamsux dot atnf dot csiro dot au (03-Jul-2002 10:22)

An error in my last example:
$b = sprintf("%30.s", $a);
will only add enough spaces before $a to pad the spaces + strlen($a) to 30 places.

My method of centering fixed text in a 72 character width space is:

$a = "Some string here";
$lwidth = 36; // 72/2
$b = sprintf("%".($lwidth + round(strlen($a)/2)).".s", $a);

eden_zero_x at hotmail dot com (26-Jun-2002 10:05)

Well I came up with this one, extremely simple. instead of writing <span class="class">hello</a>
you can write: print class('class','hello'); using sprintf
-----------------------------
function class_ ($class, $text=false)
 {
    return sprintf ("<span class=\"%s\">%s</span>",
        $class,
        ($text ? $text : $class)
    );
 }
-----------------------------

shgyn at binabakti dot or dot id (01-Jun-2002 03:57)

Previously submitted sci() function to get scientific representation of a number is not working with 0 and negative numbers. So, here is the modified version:

function sci($x, $d=-1) {
    $min=($x<0)?"-":"";
    $x=abs($x); 
    $e=floor(($x!=0)?log10($x):0);
    $x*=pow(10,-$e);
    $fmt=($d>=0)?".".$d:"";
    $e=($e>=0)?"+".sprintf("%02d",$e):"-".sprintf("%02d",-$e);
    return sprintf("$min%".$fmt."fe%s",$x,$e);
}

fuchschr at surfeu dot at (20-Feb-2002 04:54)

To have a string with leading zeros use this:
$string_i = sprintf("%04s",$value)

Gives you an output with leading zeros and 4 digits.
i.e.
0001
0002
...
0010
an so on

cv at corbach dot de (10-Feb-2002 03:36)

To make radu.rendec@ines.ro's excellent function work on signed numbers you must change the first line to:

$e = floor(log10(abs($x)));

anqmb(at)yahoo.co.jp (05-Dec-2001 12:51)

Watch out the mysterious rounding rule.
<?php
$a = 4.5;
$b = sprintf("%d",$a);
$c = 4.5;
$d = sprintf("%.0f",$c);
$e = 0.45;
$f = sprintf("%.1f",$e);
print ("$b,$d,$f\n");
?>

The code above prints "4,5,0.5".
(Perl version prints "4,4,0.5".)

keeper at odi dot com dot br (27-Nov-2001 05:26)

Took me a while to find this out.
hope will save someones time.
IT ADD A CARACRER TO THE END OF A STRING

$x = sprintf("%'x-10s", "a");
echo $x;

tjchamberlain.hotmail@com (26-Mar-2001 07:16)

It is worth noting that "%5.2f" will result in a string 8 characters long (5 then the '.' then 2), not 5 characters as you might expect.

prolixmp3 at navigators dot lv (23-Mar-2001 06:55)

If you are going to create a counter which uses _symbols_ before actual digits (see, f.e., SpyLog.com counters - they are filling space with "." before, so the count like 12345 looks like "........12345"), you can use the following:

$txt = "Abracadabra"; // actual string
$fit = 16; // how many digits to use
$fill = "."; // what to fill
$digits = sprintf ("%'{$fill}{$fit}s", $txt);

Paul (a.k.a. Mr.Prolix)

voudras at nospam dot swiftslayer dot org (17-Nov-2000 02:58)

Little note about sprintf and its ilk.
if you attempt something like
$string = "dingy%sflem%dwombat";
$nbr = 5;
$name = "voudras";

$msg = sprintf("%d $string %s", $nbr, $name);

sprintf will complain about a lack in the number of arguments, this would be because of the %'s in the actual string. This can be a great benifit, but is also rather confusing if you dont realize this feature, and are passing questionable variables to sprintf (for, say perhaps logging). One way around this is using
ereg_replace("%","%%", $string); before
sending it off to sprintf. This is actually how i came across this as a problem - i had realized some time ago that i would have to test my $string for
%'s, but when running the %->%% replacement on a very large serialized object, my application timed out.
    My solution was to use
sprintf("%d %s %s", $nbr, $string, $name);
but, there was a reason i originally had done this the other way - i suppose i'll find out soon enough