sprintf

(PHP 4, PHP 5)

sprintfReturn a formatted string

Опис

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

Returns a string produced according to the formatting string format.

Параметри

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. Additionally, the character to use when padding a number may optionally be specified between the period and the digit.
  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).
    • 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.
    • u - the argument is treated as an integer, and presented as an unsigned decimal number.
    • 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).

Variables will be co-erced to a suitable type for the specifier:

Type Handling
Type Specifiers
string s
integer d, u, c, o, x, X, b
double g, G, e, E, f, F

Увага

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

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

Приклад #1 Argument swapping

<?php
$num 
5;
$location 'tree';

$format 'There are %d monkeys in the %s';
echo 
sprintf($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:

Приклад #2 Argument swapping

<?php
$format 
'The %s contains %d monkeys';
echo 
sprintf($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:

Приклад #3 Argument swapping

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

Приклад #4 Argument swapping

<?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);
?>
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.

Приклад #5 Specifying padding character

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

Наведений вище приклад виведе:

......123
000000123

Приклад #6 Position specifier with other specifiers

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

Наведений вище приклад виведе:

The tree contains 0005 monkeys

Зауваження:

Attempting to use a position specifier greater than PHP_INT_MAX will result in sprintf() generating warnings.

Увага

The c type specifier ignores padding and width

args

...

Значення, що повертаються

Returns a string produced according to the formatting string format.

Приклади

Приклад #7 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
?>

Наведений вище приклад виведе:

%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'

Приклад #8 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
?>

Наведений вище приклад виведе:

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

Приклад #9 sprintf(): zero-padded integers

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

Приклад #10 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"
?>

Приклад #11 sprintf(): scientific notation

<?php
$number 
362525200;

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

Прогляньте Також

  • printf() - Output a formatted string
  • sscanf() - Parses input from a string according to a format
  • fscanf() - Parses input from a file according to a format
  • vsprintf() - Return a formatted string
  • number_format() - Format a number with grouped thousands

add a note add a note

User Contributed Notes 35 notes

up
69
remy dot damour at -please-no-spam-laposte dot net
13 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%'
?>
up
60
Alex R. Gibbs
9 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  |
up
3
Anderson
3 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]
*/
?>
up
18
kontakt at myseosolution dot de
7 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.
up
13
timo dot frenay at gmail dot com
11 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.
up
9
splogamurugan at gmail dot com
13 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.
up
7
no dot email dot address at example dot com
20 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.
up
10
dwieeb at gmail dot com
12 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)));
}
?>
up
10
php at sharpdreams dot com
18 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
?>
up
10
jfgrissom at gmail dot com
13 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.
up
9
viktor at textalk dot com
13 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);
  }
}
?>
up
9
Pacogliss
17 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 ;-).
up
4
abiltcliffe at bigfoot.com
20 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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6
Hayley Watson
10 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");
?>
up
1
Nathan Alan
5 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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5
john at jbwalker dot com
8 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.
up
2
nmmm at nmmm dot nu
7 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"
up
3
ian dot w dot davis at gmail dot com
17 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.
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3
carmageddon at gmail dot com
11 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.
up
4
nate at frickenate dot com
13 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));
}

?>
up
2
php at mikeboers dot com
14 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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2
hdimac at gmail dot com
8 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.
up
2
krzysiek dot 333 at gmail dot com - zryty dot hekko dot pl
11 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]);
}
?>
up
2
Andrew dot Wright at spamsux dot atnf dot csiro dot au
20 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);
up
1
geertdd at gmail dot com
12 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
?>
up
2
John Walker
13 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.
up
1
Astone
13 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!
up
1
ignat dot scheglovskiy at gmail dot com
10 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
?>
up
1
scott dot gardner at mac dot com
14 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);
up
1
jrpozo at conclase dot net
17 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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2
Anonymous
5 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);
up
0
Sam Bull
7 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));
up
0
ivan at php dot net
8 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);
up
-2
Mirek Z...
2 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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-6
Anonymous
3 years ago
I have written a wrapper for sprintf. Add a new %S  (upper case s) where the number indicates the number of characters and not bytes.
This is useful for formatting utf-8 strings.

<?php
function SacSprintf( $format) {
       
$argv = func_get_args() ;
       
array_shift($argv) ;

       
$offset = 0;
       
$i = 0;
        while(
preg_match("^A%[+-]*[.]*([0-9.]*)([a-z])^Ai", $format, $match, PREG_OFFSET_CAPTURE, $offset)) {
                if(
$match[2][0] == 'S') {
                        if(
$match[1][0] != '') {
                               
$t1 = explode('.', $match[1][0]);
                               
$t1[0] = intval($t1[0]) + strlen($argv[$i]) - strlen(utf8_decode($argv[$i]));
                               
$l1 = strlen($match[1][0]);
                               
$t2 = implode('.', $t1);
                               
$l2 = strlen($t2) - $l1;
                               
$format = substr_replace( $format, $t2, $match[1][1], strlen($match[1][0]));
                               
$offset += $l2;
                               
$match[2][1] += $l2;
                        }   
                       
$format[$match[2][1]] = 's';
                }   
               
$offset += $match[2][1];
               
$i++;
        }   
        return
vsprintf($format, $argv) ;
}

echo
"<pre>\n";
echo
"      1234567890123456789012345678901234567890\n";
echo
sprintf("Hola, %-20s is my name\n", "José Luis jiménez");
echo
SacSprintf("Hola, %-20S is my name\n", "José Luis jiménez");
echo
"</pre>\n";
?>

The output will be:
      1234567890123456789012345678901234567890
Hola, José Luis jiménez  is my name
Hola, José Luis jiménez    is my name
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