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sprintf

(PHP 4, PHP 5, PHP 7, PHP 8)

sprintf — 返回格式化字符串

说明

sprintf(string $format, mixed ...$values): string

返回一个根据格式化字符串 format 生成的字符串。

参数

format

format 字符串通常由零或多个指令组成：普通字符（不包含 %）——直接复制到结果，转换规范——获取每个参数的结果。

转换规范遵循此原型： %[argnum$][flags][width][.precision]specifier.

Argnum

整数后跟美元符号 $，用于指定转换中要处理的参数数量。

标志
标志	说明
`-`	在指定字段宽度时左对齐，默认右对齐
`+`	正数的加号 `+`前缀，默认负数的前缀是负号。
(space)	空格填充结果。这是默认设置。
`0`	仅用 0 进行左侧数字填充。使用 `s` 标志符可以右侧填充。
`'`(char)	用字符（char）填充结果。

Width

要么是整数，表示转换结果应该有多少个字符（最少），要么是 *。如果使用 *，那么宽度将作为额外的整数值提供，位于格式化符号之前。

Precision

小数点 .，可选的后跟整数或者 *，其含义取决于格式化符号：

e、E、f、F 标志符：小数点后需要打印的位数（默认是 6）。
g、G、h、H 标志符：这是要打印的最大有效位数。
s 标志符：充当分界点，为字符串设置最大字符限制。

注意: 如果小数点没有明确的精度值，则假设是 0。如果使用 *，则精度将作为额外的整数值提供，位于格式化符号之前。

**标志符**
标志符	说明
`%`	字面意思的百分号字符。不需要参数。
`b`	参数视为整数并以二进制数字呈现。
`c`	参数视为整数并以 ASCII 字符呈现。
`d`	参数视为整数并以（有符号）十进制数字呈现。
`e`	参数当做科学符号处理（例如 1.2e+2）。
`E`	与 `e` 标志符相同，但使用大写字母（例如 1.2E+2）。
`f`	参数当做浮点数处理且作为浮点数呈现（locale aware）。
`F`	参数当做浮点数处理且作为浮点数呈现（non-locale aware）。
`g`	通用格式。 Let P equal the precision if nonzero, 6 if the precision is omitted, or 1 if the precision is zero. Then, if a conversion with style E would have an exponent of X: If P > X ≥ −4, the conversion is with style f and precision P − (X + 1). Otherwise, the conversion is with style e and precision P − 1.
`G`	Like the `g` specifier but uses `E` and `f`.
`h`	Like the `g` specifier but uses `F`. Available as of PHP 8.0.0.
`H`	Like the `g` specifier but uses `E` and `F`. Available as of PHP 8.0.0.
`o`	参数视为整数并以八进制数字来呈现。
`s`	参数视为字符串来呈现。
`u`	参数视为整数并以无符号十进制数字呈现。
`x`	参数视为整数并作为十六进制数字呈现（带小写字母）。
`X`	参数视为整数并作为十六进制数字呈现（带大写字母）。

警告

c 类型标志符忽略填充和宽度

警告

Attempting to use a combination of the string and width specifiers with character sets that require more than one byte per character may result in unexpected results

变量将会强制转换为适合标志符的类型：

**类型处理**
类型	标志符
string	`s`
int	`d`, `u`, `c`, `o`, `x`, `X`, `b`
float	`e`, `E`, `f`, `F`, `g`, `G`, `h`, `H`

values

返回值

返回一个根据格式化字符串 format 生成的字符串。

错误／异常

从 PHP 8.0.0 开始，如果参数个数为零，将抛出 ValueError。在 PHP 8.0.0 之前，会发出 E_WARNING。

从 PHP 8.0.0 开始，如果 [width] 小于零或大于 PHP_INT_MAX，则会抛出 ValueError。在 PHP 8.0.0 之前，会发出 E_WARNING。

从 PHP 8.0.0 开始，如果 [precision] 小于零或大于 PHP_INT_MAX，则会抛出 ValueError。在 PHP 8.0.0 之前，会发出 E_WARNING。

从 PHP 8.0.0 开始，当传递的参数少于所需的参数时会抛出 ArgumentCountError。在 PHP 8.0.0 之前，返回 false 并发出 E_WARNING。

更新日志

版本	说明
8.0.0	此函数失败时不再返回 `false`。
8.0.0	如果参数个数为零则抛出 ValueError；以前该函数则会发出 `E_WARNING`。
8.0.0	如果 `[width]` 小于零或大于 `PHP_INT_MAX`，则抛出 ValueError；以前该函数则会发出 `E_WARNING`。
8.0.0	如果 `[precision]` 小于零或大于 `PHP_INT_MAX`，则抛出 ValueError；以前该函数则会发出 `E_WARNING`。
8.0.0	当传递的参数少于所需的参数时抛出 ArgumentCountError；以前该函数则会发出 `E_WARNING`。

示例

示例 #1 参数替换

支持按顺序用参数替换格式字符串里的占位符。

<?php
$num = 5;
$location = 'tree';

$format = 'There are %d monkeys in the %s';
echo sprintf($format, $num, $location);
?>

以上示例会输出：

There are 5 monkeys in the tree

假设，我们想把它国际化，在一个单独的文件中创建格式字符串，我们将它重写为：

<?php
$format = 'The %s contains %d monkeys';
echo sprintf($format, $num, $location);
?>

我们现在有一个问题。格式字符串中占位符的顺序与代码中参数的顺序不匹配。我们希望保持代码原样，并在格式字符串中简单地指出占位符引用的参数。我们可以这样写格式化字符串：

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

另外一个好处是占位符可以重复使用，而无需在代码中添加更多参数。

<?php
$format = 'The %2$s contains %1$d monkeys.
           That\'s a nice %2$s full of %1$d monkeys.';
echo sprintf($format, $num, $location);
?>

当使用参数替换时，n$ 位置指示符 必须紧跟在百分号（%）之后，在任何其他指示符之前，如下所示。

示例 #2 指定填充字符

<?php
echo sprintf("%'.9d\n", 123);
echo sprintf("%'.09d\n", 123);
?>

以上示例会输出：

......123
000000123

示例 #3 位置说明符与其他说明符

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

以上示例会输出：

The tree contains 0005 monkeys

示例 #4 sprintf()：零填充整数

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

示例 #5 sprintf()：货币格式

<?php
$money1 = 68.75;
$money2 = 54.35;
$money = $money1 + $money2;
echo $money;
echo "\n";
$formatted = sprintf("%01.2f", $money);
echo $formatted;
?>

以上示例会输出：

123.1
123.10

示例 #6 sprintf()：科学记数法

<?php
$number = 362525200;

echo sprintf("%.3e", $number);
?>

以上示例会输出：

3.625e+8

参见

printf() - 输出格式化字符串
fprintf() - 将格式化后的字符串写入到流
vprintf() - 输出格式化字符串
vsprintf() - 返回格式化字符串
vfprintf() - 将格式化字符串写入流
sscanf() - 根据指定格式解析输入的字符
fscanf() - 从文件中格式化输入
number_format() - 以千位分隔符方式格式化一个数字
date() - 格式化 Unix 时间戳

add a note

User Contributed Notes 36 notes

down

103

remy dot damour at -please-no-spam-laposte dot net ¶

15 years ago


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%'
?>

down

Alex R. Gibbs ¶

11 years ago


1.  A plus sign ('+') means put a '+' before positive numbers while a minus sign ('-') means left justify.  The documentation incorrectly states that they are interchangeable.  They produce unique results that can be combined:

<?php
echo sprintf ("|%+4d|%+4d|\n",   1, -1);
echo sprintf ("|%-4d|%-4d|\n",   1, -1);
echo sprintf ("|%+-4d|%+-4d|\n", 1, -1);
?>

outputs:

|  +1|  -1|
|1   |-1  |
|+1  |-1  |

2.  Padding with a '0' is different than padding with other characters.  Zeros will only be added at the front of a number, after any sign.  Other characters will be added before the sign, or after the number:

<?php
echo sprintf ("|%04d|\n",   -2);
echo sprintf ("|%':4d|\n",  -2);
echo sprintf ("|%-':4d|\n", -2);

// Specifying both "-" and "0" creates a conflict with unexpected results:
echo sprintf ("|%-04d|\n",  -2);

// Padding with other digits behaves like other non-zero characters:
echo sprintf ("|%-'14d|\n", -2);
echo sprintf ("|%-'04d|\n", -2);
?>

outputs:

|-002|
|::-2|
|-2::|
|-2  |
|-211|
|-2  |

down

timo dot frenay at gmail dot com ¶

13 years ago


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.

down

kontakt at myseosolution dot de ¶

9 years ago


There are already some comments on using sprintf to force leading leading zeros but the examples only include integers. I needed leading zeros on floating point numbers and was surprised that it didn't work as expected.

Example:
<?php
sprintf('%02d', 1);
?>

This will result in 01. However, trying the same for a float with precision doesn't work:

<?php
sprintf('%02.2f', 1);
?>

Yields 1.00. 

This threw me a little off. To get the desired result, one needs to add the precision (2) and the length of the decimal seperator "." (1). So the correct pattern would be

<?php
sprintf('%05.2f', 1);
?>

Output: 01.00

Please see http://stackoverflow.com/a/28739819/413531 for a more detailed explanation.

down

nate at frickenate dot com ¶

14 years ago


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));
}

?>

down

Anonymous ¶

7 years ago


Be cafeful while trying to refactor longer strings with repeated placeholders like 

    sprintf("Hi %s. Your name is %s", $name, $name);

to use argument numbering:

   sprintf("Hi %1$s. Your name is %1$s", $name);

This will nuke you at **runtime**, because of `$s` thing being handled as variable. If you got no $s for substitution, notice will be thrown. 

The solution is to use single quotes to prevent variable substitution in string:

   sprintf('Hi %1$s. Your name is %1$s', $name);

If you need variable substitution, then you'd need to split your string to keep it in single quotes:

   sprintf("Hi " . '%1$s' . ". Your {$variable} is " . '%1$s', $name);

down

jfgrissom at gmail dot com ¶

15 years ago


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.

down

ian dot w dot davis at gmail dot com ¶

19 years ago


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.

down

Anderson ¶

4 years ago


The old "monkey" example which helped me a lot has sadly disappeared.

I'll Re-post it in comment as a memory.

<?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

/*
%b = '10100111101010011010101101'
%c = 'A'
%d = '43951789'
%e = '4.395179e+7'
%u = '43951789'
%u = '18446744073665599827'
%f = '43951789.000000'
%o = '247523255'
%s = '43951789'
%x = '29ea6ad'
%X = '29EA6AD'
%+d = '+43951789'
%+d = '-43951789'
*/

$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

/*
[monkey]
[    monkey]
[monkey    ]
[0000monkey]
[####monkey]
[many monke]
*/
?>

down

viktor at textalk dot com ¶

15 years ago


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);
  }
}
?>

down

dwieeb at gmail dot com ¶

14 years ago


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)));
}
?>

down

abiltcliffe at bigfoot.com ¶

22 years ago


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).

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carmageddon at gmail dot com ¶

13 years ago


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.

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Pacogliss ¶

19 years ago


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 ;-).

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no dot email dot address at example dot com ¶

22 years ago


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.

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Hayley Watson ¶

12 years ago


If you use argument numbering, then format specifications with the same number get the same argument; this can save repeating the argument in the function call.

<?php

$pattern = '%1$s %1$\'#10s %1$s!';

printf($pattern, "badgers");
?>

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splogamurugan at gmail dot com ¶

15 years ago


$format = 'There are %1$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.

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php at mikeboers dot com ¶

16 years ago


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!

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krzysiek dot 333 at gmail dot com - zryty dot hekko dot pl ¶

13 years ago


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]);
}
?>

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john at jbwalker dot com ¶

10 years ago


I couldn't find what should be a WARNING in the documentation above, that if you have more specifiers than variables to match them sprintf returns NOTHING. This fact, IMHO, should also be noted under return values.

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php at sharpdreams dot com ¶

20 years ago


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
?>

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geertdd at gmail dot com ¶

14 years ago


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
?>

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Nathan Alan ¶

7 years ago


Just wanted to add that to get the remaining text from the string, you need to add the following as a variable in your scanf

%[ -~]

Example:

sscanf($sql, "[%d,%d]%[ -~]", $sheet_id, $column, $remaining_sql);

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ignat dot scheglovskiy at gmail dot com ¶

12 years ago


Here is an example how alignment, padding and precision specifier can be used to print formatted list of items:

<?php

$out = "The Books\n";
$books = array("Book 1", "Book 2", "Book 3");
$pages = array("123 pages ", "234 pages", "345 pages");
for ($i = 0; $i < count($books); $i++) {
    $out .= sprintf("%'.-20s%'.7.4s\n", $books[$i], $pages[$i]);
}
echo $out;

// Outputs:
// 
// The Books
// Book 1.................123 
// Book 2.................234 
// Book 3.................345 
?>

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jrpozo at conclase dot net ¶

19 years ago


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.

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hdimac at gmail dot com ¶

10 years ago


In the examples, is being shown printf, but it should say sprintf, which is the function being explained... just a simple edition mistake.

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nmmm at nmmm dot nu ¶

9 years ago


php printf and sprintf not seems to support star "*" formatting.

here is an example:

printf("%*d\n",3,5);

this will print just "d" instead of "<two spaces>5"

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scott dot gardner at mac dot com ¶

16 years ago


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);

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John Walker ¶

15 years ago


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.

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Anonymous ¶

2 years ago


If the format string is enclosed in double-quotes (""), you need to escape the dollar sign after argnum with a backslash character (\), like this %1\$s, so that the PHP doesn't try to interpret them as variable. Using a backslash like this is called an escape sequence.

<?php
// Sample string
$number = 499;
$format = "The number without decimal points: %1\$d, and the number with two decimal points: %1\$.2f";

// Formatting and print the string
printf($format, $number);
?>

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Andrew dot Wright at spamsux dot atnf dot csiro dot au ¶

22 years ago


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);

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ivan at php dot net ¶

10 years ago


There is a minor issue in a code of mb_vsprintf function from viktor at textalk dot com.

In "truncate $arg" section the following line:
  $arg = mb_substr($precision,0,$precision,$encoding);
needs to be replaced with:
  $arg = mb_substr($arg,0,$precision,$encoding);

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Astone ¶

15 years ago


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!

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-1

Sam Bull ¶

9 years ago


Fix for sprintfn function for named arguments (http://php.net/manual/en/function.sprintf.php#94608):

Change the first line from:
  $arg_nums = array_slice(array_flip(array_keys(array(0 => 0) + $args)), 1);
to:
  $arg_nums = array_keys($args);
  array_unshift($arg_nums, 0);
  $arg_nums = array_flip(array_slice($arg_nums, 1, NULL, true));

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-3

Mirek Z... ¶

4 years ago


I've performed a simple speed test. sprintf against PHP string concatenation operator. Test was performed on PHP 7.3 for 1 million interations.

I run this several times and what I've noted that string concatenation took about 2.9 seconds, sprintf took 4.3 seconds.
I was thinking about what is faster, what is better to do when we're going to format our string (for example, the message to the user or for log purposes) containing some variables values. Is it better to concatenate string with variables using operator (dot ".") or to use sprintf. The answer is: when you do not plan to implement any multilanguage mechanisms and feel good with hardcoding some texts, the "dot" is almost 1.5 times faster!

Here's the code:

echo 'Start' . PHP_EOL;
$vS_text = 'some text';
$vS = '';
$vf = microtime(true);
for ($vI = 0; $vI < 1000000; $vI++) {
    $vS = 'Start ' . $vI . ' ' . $vS_text . ' ' . $vf . ' end';
}
$vf = microtime(true) - $vf;
echo 'Concat:' . $vf . PHP_EOL;
$vS = '';
$vf = microtime(true);
for ($vI = 0; $vI < 1000000; $vI++) {
    $vS = sprintf('Start %d %s %f end', $vI, $vS_text, $vf);
}
$vf = microtime(true) - $vf;
echo 'Spritf:' . $vf . PHP_EOL;

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-4

2838132019 at qq dot com ¶

3 years ago


echo sprintf("%.2f", "123456789012345.82");  
// result: 123456789012345.81

echo sprintf("%.2f", "123456789012345.85");
// result: 123456789012345.84

echo sprintf("%.2f", "123456789012345.87");
//result:  123456789012345.88

echo sprintf("%.2f", "123456789012345.820"); 
//result: 123456789012345.81

echo sprintf("%.2f", "123456789012345.821");  
//result: 123456789012345.83

echo sprintf("%.2f", "123456789012345.828");  
//result: 123456789012345.83

echo sprintf("%.2f", "123456789012345.8209"); 
//result : 123456789012345.83

echo sprintf("%.2f", "1234567890123456.82"); 
//result: 1234567890123456.75

echo sprintf("%.2f", "123456789012345.82002"); 
//result: 123456789012345.81

echo sprintf("%.2f", "123456789012345.820001"); 
//result: 123456789012345.81

echo sprintf("%.2f", "123456789012345.820101");
//result: 123456789012345.81

echo sprintf("%.2f", "123456789012345.820201");
//result: 123456789012345.81

echo sprintf("%.2f", "123456789012345.820301");
//result: 123456789012345.81

echo sprintf("%.2f", "123456789012345.820401");
//result: 123456789012345.83

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