PHP: sprintf - Manual

Description

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

Returns a string produced according to the formatting string 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:

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.
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.
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.
An optional number, a width specifier that says how many characters (minimum) this conversion should result in.
An optional precision specifier 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.

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).

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.

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).

As of PHP 4.0.6 the format string supports argument numbering/swapping. Here is an example:

Przykład 1. Argument swapping


<?php

$format = "There are %d monkeys in the %s";

printf($format, $num, $location);

?>

This might 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:

Przykład 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:

Przykład 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:

Przykład 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);

?>

Examples

Przykład 5. 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

?>

The printout of this program would be:

%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'

Przykład 6. 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

?>

The printout of this program would be:

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

Przykład 7. sprintf(): zero-padded integers


<?php

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

?>

Przykład 8. 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"

?>

Przykład 9. sprintf(): scientific notation


<?php

$number = 362525200;



echo sprintf("%.3e", $number); // outputs 3.63e+8

?>

User Contributed Notes


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 = "x