sprintf

add a note User Contributed Notes

Anonymous
17-Oct-2006 07:04


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 05:48


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
13-Aug-2006 02:54


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
11-Aug-2006 05:54


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
07-Aug-2006 01:35


<?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 04:51


<?

/**

 * [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 11:21


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
19-Dec-2005 04:57


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.

jonybd
14-Nov-2005 10:02


Time ? Format 



<?php 



$v_Dur = "66";

$v_Dur = floor($v_Dur/60) . ":" .  number_format( fmod(($v_Dur/60)*60,60) )  ;

echo "HH:MM========" . $v_Dur;



echo "<br>";



$v_Dur = "66";

$v_Dur = floor($v_Dur/60) . ":" .  sprintf("%02s",number_format( fmod(($v_Dur/60)*60,60) )  );

echo "HH:MM========" . $v_Dur;



?>

tim dot brouckaert dot NOSPAM at gmail dot com
12-Oct-2005 08:35


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 12:47


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 02:33


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 10:03


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 03:08


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 03:20


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

henke dot andersson at comhem dot se
15-Apr-2005 11:07


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
01-Feb-2005 06:03


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 11:13


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
11-Jan-2005 02:58


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
12-Aug-2004 06:58


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
16-Jun-2004 05:47


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
09-May-2004 05:13


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 10:09


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
30-Mar-2004 01:16


A really working one:

<?php

function cutzero($value) { 

   return preg_replace("/(\.?)0+$/", "", $value);

}

?>

06-Mar-2004 02:54


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") ?

martin at schwedes dot com
10-Jul-2003 06:45


decision within sprintf:



$a = "today";

$b = sprintf('This is %s', $a=='today' ? 'today':'not today');

echo $b;

// result: This is today

Rene dot Leonhardt at agritec24 dot com
17-May-2003 01:02


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 05:55


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 09:06


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
03-Dec-2002 06:52


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 09:29


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
11-Sep-2002 02:01


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 05:22


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
27-Jun-2002 05:05


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 10:57


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
21-Feb-2002 12:54


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 11:36


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)));

radu dot rendec at ines dot ro
09-Jan-2002 10:49


The 'e' format specifier is not documented. However, it seems to work, but without showing the exponential part of the number.



This is a function to get the scientific representation of a number:



function sci($x, $d=-1) {

    $e=floor(log10($x));

    $x*=pow(10,-$e);

    $fmt=($d>=0)?".".$d:"";

    $e=($e>=0)?"+".sprintf("%02d",$e):"-".sprintf("%02d",-$e);

    return sprintf("%".$fmt."fe%s",$x,$e);

}



It takes the number as the first parameter and the precision as the second. The precision is optional. The default precision for the 'f' format specifier is used if no precision is specified.

anqmb(at)yahoo.co.jp
05-Dec-2001 08:51


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 01:26


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;

target_rex at hotmail dot com
15-Apr-2001 10:20


$a = 5;


// $a is a int


echo $5;


// Outputs:"5";


// If you would like to print $a as a bin,(101) like: 00000101 (8 digits)


sprintf("%8b", $a) // Witch returns exatly 00000101 (8 digits)





// My function looked like:


  //////////////////////////////////////////


  // By DrRex - www.DrRex.dk - 15/04-2001 //


  // string bin(int dec)                  //


  //////////////////////////////////////////


  function bin($dec){


    $bin = sprintf("%8b", $dec);


    return $bin;


  }


  //////////////////////////////////////////





// Very short exampels how to use bin()





  echo "\n1. 128(10) == ".bin(128)."(2)";





  $hits = 100;


  echo "\n2. Loaded ".bin($hits)."(2) times! Bib!";





// Not very usefull, nobody understands the number, exept if small counters like this one. If it wasn't 8(2) but FFFFFF(16) digits. I would give up...





// This would output:


  1. 128(10) == 10000000(2)


  2. Loaded 01100100(2) times! Bib!





-------------------------------------------------


Greetings from Christiania, Copenhagen, Denmark!


All code by DrRex


www.DrRex.dk

tjchamberlain.hotmail@com
26-Mar-2001 03:16


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
24-Mar-2001 02:55


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 10:58


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

paolini at kahuna dot sdsu dot edu
14-Apr-1999 04:12


Hey folks, don't forget to prefix a precision specifier with a period '.'!


Thus, to print a floating point number,


say $x, with two digits after the decimal point you would write: 





printf( "%.2f", $x );

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