sprintf

(PHP 4, PHP 5, PHP 7)

sprintfDevuelve un string formateado

Descripción

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

Devuelve un string producido según el string de formateo dado por format.

Parámetros

format

El string de formateo está compuesto de cero o más directivas: caracteres ordinarios (excluyendo %) que son copiados directamente al resultado, y especificaciones de conversión, donde cada una de las cuales da lugar a extraer su propio parámetro. Esto se aplica tanto para sprintf() como para printf().

Cada especificación de conversión consiste en un signo de porcentaje (%), seguido por uno o más de estos elementos, en orden:

  1. Un especificador de signo opcional que fuerza a usar un signo (- o +) en un número. Por defecto, sólo el signo - se utiliza en un número si es negativo. Esta especificación fuerza números positivos para que también tengan adjunto el signo + (agregado en PHP 4.3.0).
  2. Un especificador de relleno opcional que indica qué carácter se utiliza para rellenar el resultado hasta el tamaño justo del string. Este puede ser un carácter de espacio o un 0 (el carácter cero). El valor por defecto es rellenar con espacios. Un carácter de relleno alternativo se puede especificar prefijándolo con una comilla simple ('). Ver los ejemplos más adelante.
  3. Un especificador de alineación opcional que indica si el resultado debe ser alineado a la izquierda o a la derecha. El valor por defecto es justificado a la derecha, un carácter - lo justificará a la izquierda.
  4. Un número opcional, un especificador de ancho que indica de cuántos caracteres (mínimo) resultará esta conversión.
  5. Un especificador de precisión opcional en la forma de un punto (.) seguido de un string opcional de dígitos decimales que indica cuántos dígitos decimales deben mostrarse para los números de punto flotante. Cuando se utiliza este especificador con un string, actúa como un punto de corte, estableciendo un límite máximo de caracteres al string. Además, el carácter para empleado cuando se rellena un número podría especificarse opcionalmente entre el punto y el dígito.
  6. Un especificador de tipo que indica con qué tipo deben ser tratados los datos del argumento. Los tipos posibles son:

    • % - un carácter de porcentaje literal. No se requiere argumento.
    • b - el argumento es tratado como un valor de tipo integer y presentado como un número binario.
    • c - el argumento es tratado como un valor de tipo integer y presentado como el carácter con ese valor ASCII.
    • d - el argumento es tratado como un valor de tipo integer y presentado como un número decimal (con signo).
    • e - el argumento es tratado con notación científica (e.g. 1.2e+2). El especificador de precisión indica el número de dígitos después del punto decimal a partir de PHP 5.2.1. En versiones anteriores, se tomó como el número de dígitos significativos (menos uno).
    • E - como %e pero utiliza la letra mayúscula (e.g. 1.2E+2).
    • f - el argumento es tratado como un valor de tipo float y presentado como un número de punto flotante (considerando la configuración regional).
    • F - el argumento es tratado como un valor de tipo float y presentado como un número de punto flotante (no considerando la configuración regional). Disponible desde PHP 4.3.10 y PHP 5.0.3.
    • g - lo mismo que %e y %f.
    • G - lo mismo que %E y %f.
    • o - el argumento es tratado como un valor de tipo integer y presentado como un número octal.
    • s - el argumento es tratado y presentado como un string.
    • u - el argumento es tratado como un valor de tipo integer y presentado como un número decimal sin signo.
    • x - el argumento es tratado como un valor de tipo integer y presentado como un número hexadecimal (con las letras en minúsculas).
    • X - el argumento es tratado como un valor de tipo integer y presentado como un número hexadecimal (con las letras en mayúsculas).

Las variables serán forzadas por el especificador a un tipo adecuado:

Manejo de tipos
Tipo Especificador
string s
integer d, u, c, o, x, X, b
double g, G, e, E, f, F

Advertencia

Intentar usar una combinación de especificadores de string y ancho con conjuntos de caracteres que requieran más de un byte por carácter podría tener resultados inesperados.

El string de formato soporta la numeración/intercambio de argumentos. Aquí está un ejemplo:

Ejemplo #1 Intercambio de argumentos

<?php
$num 
5;
$ubicación 'árbol';

$formato 'Hay %d monos en el %s';
echo 
sprintf($formato$num$ubicación);
?>
Esto producirá " Hay 5 monos en el árbol". Pero imaginemos que estamos creando un string de formato en un fichero aparte, generalmente por que nos gustaría internacionalizarlo, reescribiéndolo así:

Ejemplo #2 Intercambio de argumentos

<?php
$formato 
'El %s contiene %d monos';
echo 
sprintf($formato$num$ubicación);
?>
Ahora tenemos un problema. El orden de los marcadores de posición en el string de formato no coincide con el orden de los argumentos en el código. Nos gustaría dejar el código tal cual y simplemente indicar en el string de formato a cuáles argumentos de los marcadores de posición se refieren. Tendríamos que escribir el string de formato de esta forma:

Ejemplo #3 Intercambio de argumentos

<?php
$formato 
'El %2$s contiene %1$d monos';
echo 
sprintf($formato$num$ubicación);
?>
Un beneficio adicional es que se pueden repetir los marcadores de posición sin agregar más argumentos en el código. Por ejemplo:

Ejemplo #4 Intercambio de argumentos

<?php
$formato 
'El %2$s contiene %1$d monos.
            Es un bonito %2$s con %1$d monos.'
;
echo 
sprintf($formato$num$ubicación);
?>
Cuando se utiliza el intercambio de argumentos, el especificador de posición n$ debe ir inmediatamente después del signo de porcentaje (%), antes de cualquier otro especificador, tal como se muestra en el ejemplo siguiente.

Ejemplo #5 Especificar un carácter de relleno

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

El resultado del ejemplo sería:

......123
000000123

Ejemplo #6 Especificador de posición con otros especificadores

<?php
$formato 
'El %2$s contiene %1$04d monos';
echo 
sprintf($formato$num$ubicación);
?>

El resultado del ejemplo sería:

 El árbol contiene 0005 monos

Nota:

Tratar de utilizar marcadores de posición mayores que PHP_INT_MAX provocará que sprintf() genere mensajes de advertencia.

Advertencia

El especificador de tipo c ignora el relleno y el ancho

args

...

Valores devueltos

Devuelve un string producido de acuerdo con el string de formato format.

Ejemplos

Ejemplo #7 printf(): ejemplos varios

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

// observar el doble %%, esto muestra un carácter '%' literal
printf("%%b = '%b'\n"$n); // representación binaria
printf("%%c = '%c'\n"$c); // muestra el carácter ascii, igual que la función chr()
printf("%%d = '%d'\n"$n); // representación estándar de un entero
printf("%%e = '%e'\n"$n); // notación científica
printf("%%u = '%u'\n"$n); // representación sin signo de un entero positivo
printf("%%u = '%u'\n"$u); // representación sin signo de un entero negativo
printf("%%f = '%f'\n"$n); // representación de punto flotante
printf("%%o = '%o'\n"$n); // representación octal
printf("%%s = '%s'\n"$n); // representación en una cadena
printf("%%x = '%x'\n"$n); // representación hexadecimal (minúsculas)
printf("%%X = '%X'\n"$n); // representación hexadecimal (mayúsculas)

printf("%%+d = '%+d'\n"$n); // especificador de signo sobre un entero positivo
printf("%%+d = '%+d'\n"$u); // especificador de signo sobre un entero negativo
?>

El resultado del ejemplo sería:

%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'

Ejemplo #8 printf(): especificadores de string

<?php
$s 
'mono';
$t 'muchos monos';

printf("[%s]\n",      $s); // salida estándar de string 
printf("[%10s]\n",    $s); // justificación a la derecha con espacios
printf("[%-10s]\n",   $s); // justificación a la izquierda con espacios
printf("[%010s]\n",   $s); // rellenado con ceros también funciona con strings
printf("[%'#10s]\n",  $s); // utiliza el carácter de relleno personalizado '#'
printf("[%10.10s]\n"$t); // justificación a la izquierda pero con un corte a los 10 caracteres
?>

El resultado del ejemplo sería:

[mono]
[      mono]
[mono      ]
[000000mono]
[######mono]
[muchos mon]

Ejemplo #9 sprintf(): valores de tipo integer rellenados con ceros

<?php
$fecha_iso 
sprintf("%04d-%02d-%02d"$año$mes$día);
?>

Ejemplo #10 sprintf(): formato de moneda

<?php
$dinero1 
68.75;
$dinero2 54.35;
$dinero $dinero1 $dinero2;
// echo $dinero producirá "123.1";
$formateado sprintf("%01.2f"$dinero);
// echo $formateado producirá "123.10"
?>

Ejemplo #11 sprintf(): notación científica

<?php
$número 
362525200;

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

Ver también

  • printf() - Imprimir una cadena con formato
  • sscanf() - Interpreta un string de entrada de acuerdo con un formato
  • fscanf() - Analiza la entrada desde un archivo de acuerdo a un formato
  • vsprintf() - Devuelve una cadena con formato
  • number_format() - Formatear un número con los millares agrupados
  • date() - Dar formato a la fecha/hora local

add a note add a note

User Contributed Notes 40 notes

up
54
Alex R. Gibbs
6 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
43
remy dot damour at -please-no-spam-laposte dot net
10 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
3
thavarajan at gmail dot com
1 year ago
<?php
echo sprintf("%+08d", 0). "<Br>";
echo
sprintf("%+07d", 0). "<Br>";
echo
sprintf("%+06d", 0). "<Br>";
?>

Will produce an output
+0000000
+000000
+00000
up
19
kontakt at myseosolution dot de
4 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
9
timo dot frenay at gmail dot com
8 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
11
jfgrissom at gmail dot com
10 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
php at sharpdreams dot com
15 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
6
john at jbwalker dot com
5 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
4
no dot email dot address at example dot com
17 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
4
abiltcliffe at bigfoot.com
17 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).
up
7
dwieeb at gmail dot com
9 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
8
viktor at textalk dot com
10 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
15
Jay Gilford
10 years ago
I created this function a while back to save on having to combine mysql_real_escape_string onto all the params passed into a sprintf. it works literally the same as the sprintf other than that it doesn't require you to escape your inputs. Hope its of some use to people

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

Regards
Jay
Jaygilford.com
up
6
david at rayninfo dot co dot uk
14 years ago
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
up
8
Pacogliss
14 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
krzysiek dot 333 at gmail dot com - zryty dot hekko dot pl
8 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
4
carmageddon at gmail dot com
8 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
3
hdimac at gmail dot com
5 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
7
christian at wenz dot org
14 years ago
@ henke dot andersson at comhem dot se: Use vprintf()/vsprintf() for that.
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4
splogamurugan at gmail dot com
10 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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5
Hayley Watson
7 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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1
php at mikeboers dot com
11 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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4
nate at frickenate dot com
9 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));
}

?>
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3
ian dot w dot davis at gmail dot com
14 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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4
jaimthorn at yahoo dot com
11 years ago
I needed a piece of code similar to the one Matt posted below, on the 10th of March, 2008.  However, I wasn't completely satisfied with Matt's code (sorry, Matt!  No offense intended!), because

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

What are the bugs?

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

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

<?php

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

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

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

    return
$str;
}

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

?>

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

<?php

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

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

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

<?php

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

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

Of course, by now the sprintf function is no longer something you'd want to write to mum and dad about...
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6
matt
11 years ago
Was looking for a assoc way of using sprintf but couldnt find one, probably wasnt looking hard enough so came up with this. Very very simple indeed...

<?php

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

    return
$str;
}

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

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

?>

Looks nice anyway :)
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2
Andrew dot Wright at spamsux dot atnf dot csiro dot au
17 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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2
Astone
10 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
geertdd at gmail dot com
9 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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2
John Walker
10 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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1
jrpozo at conclase dot net
14 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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1
Anonymous
2 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);
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0
Nathan Alan
2 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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0
Sam Bull
3 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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0
nmmm at nmmm dot nu
4 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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-1
Anonymous
10 months 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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0
ivan at php dot net
5 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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0
ignat dot scheglovskiy at gmail dot com
7 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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0
scott dot gardner at mac dot com
11 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", $t);
up
-1
me at umarfarooq dot net
12 years ago
/**
This function returns a formated  string with the legnth you specify
@string holds the string which you want to format
@len holds the length you want to format
**/
function formatString($string, $len)
{
    if (strlen($string) < $len)
    {
        $addchar=($len - strlen($string)) ;
        for ($i = 0; $i < $addchar; $i++)
        {
            $string=sprintf("$string%s", "0");
        }
    }
   
    if (strlen($string) > $len)
    {
        $string=substr($string,0,$len);
    }
   
    return $string;   
}
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