sscanf

(PHP 4 >= 4.0.1, PHP 5, PHP 7, PHP 8)

sscanf — Interpreta a entrada de uma string de acordo com um formato

Descrição

sscanf(string $string, string $format, mixed &...$vars): array|int|null

A função sscanf() é a análoga de entrada a printf(). sscanf() lê da string string e interpreta-a de acordo com o especificado em format.

Qualquer espaço em branco na string de formato corresponde a qualquer espaço em branco na string de entrada. Isto significa que até mesmo uma tabulação (\t) na string de formato pode corresponder a um caractere de espaço simples na string de entrada.

Parâmetros

string

A string de entrada a ser analisada.

format

O formato interpretado para string, que é descrito na documentação para sprintf() com as seguintes diferenças:

A função não reconhece a localidade.
F, g, G e b não são suportados.
D significa número decimal.
i significa inteiro com detecção de base.
n representa o número de caracteres processados até o momento.
s pára de ler em qualquer caractere de espaço em branco.
* em vez de argnum$ suprime a atribuição desta especificação de conversão.

vars

Variáveis opcionais passadas por referência que conterão os valores analisados.

Valor Retornado

Se apenas dois parâmetros forem passados para esta função, os valores interpretados serão retornados como um array. Caso contrário, se parâmetros opcionais forem passados, a função retornará o número de valores atribuídos. Os parâmetros opcionais precisam ser passados por referência.

Se houver mais substrings esperadas em format do que estiverem disponíveis na string, null será retornado.

Exemplos

Exemplo #1 Exemplo de sscanf()

<?php
// Pegando o número serial
list($serial) = sscanf("SN/2350001", "SN/%d");
// e a data de produção
$mandate = "January 01 2000";
list($month, $day, $year) = sscanf($mandate, "%s %d %d");
echo "O item $serial foi produzido em: $year-" . substr($month, 0, 3) . "-$day\n";
?>

Se parâmetros opcionais forem passados, a função retornará o número de valores atribuídos.

Exemplo #2 sscanf() - usando parâmetros opcionais

<?php
// pega informação do autor e gera uma entrada de DocBook
$auth = "24\tLewis Carroll";
$n = sscanf($auth, "%d\t%s %s", $id, $first, $last);
echo "<author id='$id'>
    <firstname>$first</firstname>
    <surname>$last</surname>
</author>\n";
?>

Veja Também

printf() - Output a formatted string
sprintf() - Return a formatted string
fprintf() - Escreve uma string formatada para um fluxo
vprintf() - Output a formatted string
vsprintf() - Return a formatted string
vfprintf() - Escreve uma string formatada para um fluxo
fscanf() - Interpreta a leitura de um arquivo de acordo com um formato
number_format() - Format a number with grouped thousands
date() - Formatar um timestamp Unix

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User Contributed Notes 18 notes

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jon at fuck dot org ¶

22 years ago


this function is a great way to get integer rgb values from the html equivalent hex.

list($r, $g, $b) = sscanf('00ccff', '%2x%2x%2x');

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elgabos at umail dot ucsb dot edu ¶

22 years ago


After playing around with this for a while, I found that if you use %[^[]] instead of %s (since php has problems with spaces when using %s) it works nicely. 

For those that aren't familiar with regular expressions, %[^[]] basically matches anything that isn't nothing.

Hope this helps. - Gabe

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mikewillitsgmail.com ¶

16 years ago


FYI - if you are trying to scan from a string which contains a filename with extension. For instance:

<?php

$out = sscanf('file_name.gif', 'file_%s.%s', $fpart1, $fpart2);

?>

The scanned string in the $fpart1 parameter turns out to be 'name.gif' and $fpart2 will be NULL.

To get around this you can simply replace the "." with a space or another "white-space like" string sequence.

I didn't see any other comments on regarding string literals which contain a '.' so I thought I'd mention it. The subtle characteristics of having "white-space delimited" content I think can be a source of usage contention. Obviously, another way to go is regular expressions in this instance, but for newer users this may be helpful.

Just in case someone else spent 10 minutes of frustration like I did. This was seen on PHP Version 5.2.3-1ubuntu6.3.

Searching the bug reports shows another users misunderstanding: http://bugs.php.net/bug.php?id=7793

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Brainiac361 ¶

19 years ago


The %[^[]]-trick may seem to work, but it doesn't!

What happens is that sscanf will simply match any characters but an opening square bracket (which is rather rare and that's why it might just seem to work).
But even worse it will expect a ]-character next and continue to match anything.

Now what you can do is make sscanf look for any character but a character that is really never used... a good choice is the linebreak "%[^\\n]", especially in combination with fscanf.

What you can also do is copy and paste any unused ascii character like #001 or something.

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leg ¶

16 years ago


@mikewillitsgmail.com:

<?php

$out = sscanf('file_name.gif', 'file_%[^.].%s', $fpart1, $fpart2);

echo '<pre>';
print_r($fpart1);
echo '<hr />';
print_r($fpart2);
echo '</pre>';

?>

output:

name
-
gif

The "^." part avoid the first searched string to be too greedy. But doesn't protect you against an "file_test.name.gif" input, with bad results!

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Victor ¶

12 years ago


One thing to note: unlike C/C++, a variable %n is assigned to will be counted in the return value.

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Vincent Jansen ¶

19 years ago


If you just wants filter out information between two parts of a string, i used the following, it works better for me then the sscanf function. 

<?php
function scanstr($zoekstr,$part1,$part2) {
$firstpos=strpos ($zoekstr, $part1)+strlen($part1);
$lastpos=strpos ($zoekstr, $part2);
$scanresult=substr ($zoekstr, $firstpos, $lastpos-$firstpos);
    return($scanresult);
}
echo scanstr ("var1=hello&var2=test&var3=more","var2=","&var3");
?>

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anonymouse ¶

18 years ago


I've seen several examples of people using brackets to define what look like regexp character classes. In my limited testing I don't think they are genuine character classes but they seem to be similar.

My task was to use sscanf() to parse an array of strings with the format:

number SPACE string_which_may_also_have_spaces

The normal %s conversion command treats spaces as some kind of delimiter. So, you can get the strings if you know beforehand how many "words" there will be. But, my input was variable.

Here's what I came up with: (note use of the dollar-sign 'end of string' hidden delimiter)

sscanf($string_to_parse,'%d %[^$]s',$num,$text);

This conversion command says "look for an integer, then a space, then any string up to the end of the string"

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codeslinger at compsalot dot com ¶

19 years ago


Security Note:

Although it is a very powerful technique, keep in mind that it is easily deceived.

Many successful exploits have been based on scanf attacks.  It should not be used on untrusted input without a lot of additional validation.

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skeltoac ¶

18 years ago


To parse a line from an Apache access log in common format:

<?php
$log = array();
$n = sscanf(trim($line), '%s %s %s [%[^]]] "%s %s %[^"]" %d %s "%[^"]" "%[^"]"',
    $log['ip'],
    $log['client'],
    $log['user'],
    $log['time'],
    $log['method'],
    $log['uri'],
    $log['prot'],
    $log['code'],
    $log['bytes'],
    $log['ref'],
    $log['agent']
);
?>

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narainsbrain at yahoo dot com ¶

23 years ago


apparently, sscanf always splits at spaces, even if spaces are not specified in the format. consider this script:



<?php

$str = "This is a\tsentence with\ttabs";

$scanned = sscanf($str, "%s\t%s\t%s");

echo join(" : ", $scanned);

?>



this echoes "This : is : a", not the expected "This is a : sentence with : tabs."

this behaviour is fine if your strings don't contain spaces, but if they do you'd be better off using explode().

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Philo ¶

4 years ago


It should also be noted that when used with sscanf both x and X produce the same output (i.e. they are case-insensitive).

<?php
var_dump(sscanf("0xdead|0XDEAD", "%X|%x")); // works

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joshmckenneyATgmailDOT(0{ ¶

19 years ago


added country code (1) to phone number function:

function formatPhone($phone) {
       if (empty($phone)) return "";
       if (strlen($phone) == 7)
               sscanf($phone, "%3s%4s", $prefix, $exchange);
       else if (strlen($phone) == 10)
               sscanf($phone, "%3s%3s%4s", $area, $prefix, $exchange);
       else if (strlen($phone) > 10)
               if(substr($phone,0,1)=='1') {
                                 sscanf($phone, "%1s%3s%3s%4s", $country, $area, $prefix, $exchange);
                             }
                             else{
                                 sscanf($phone, "%3s%3s%4s%s", $area, $prefix, $exchange, $extension);
                                }
       else
               return "unknown phone format: $phone";
       $out = "";
       $out .= isset($country) ? $country.' ' : '';
       $out .= isset($area) ? '(' . $area . ') ' : '';
       $out .= $prefix . '-' . $exchange;
       $out .= isset($extension) ? ' x' . $extension : '';
       return $out;
}

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-1

clcollie at mindspring dot com ¶

24 years ago


Actually sscanf()_always_ returns an array if you specify less return variables than format specifiers. i may change this to return a scalar if only a single format specifier exists.

  Note that sscanf() is (almost) the complete functional equivalent of its "C" counterpart, so you can do the following to get the expected effect :



   sscanf("SN/2350001","SN/%d",&$serial)



The array return was a nicety for PHP.

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-3

marcus at synchromedia dot co dot uk ¶

21 years ago


In PHP >= 4.3.0, if you use additional reference parameters, you will get this warning:

PHP Warning:  Call-time pass-by-reference has been deprecated - argument passed by value

This clearly has the potential to cause unexpected consequences (vars left empty), and will break existing code. So don't do it! These docs need updating to say this too.

The syntax:

    list($a, $b) = sscanf("hello world", "%s %s");

will work as expected, and doesn't seem to cause any problems with Apache that I've noticed.

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-4

sbarnum.pointsystems@com ¶

22 years ago


More fun with phones!  This assumes that the phone number is 10 digits, with only numeric data, but it would be easy to check the length of the string first.

function formatPhone($phone) {
        if (empty($phone)) return "";
        sscanf($phone, "%3d%3d%4d", $area, $prefix, $exchange);
        $out = @$area ? "($area) " : "";
        $out .= $prefix . '-' . $exchange;
        return $out;
}

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-9

nmmm at nmmm dot nu ¶

12 years ago


This is more like C/C++ example, but works on PHP too.



<?php

$qs = "index.php?id=34&name=john";



print_r(   sscanf($qs, "%[^?]?%[^?]")   );



$qs = "id=34&name=john";



print_r(   sscanf($qs, "id=%[^&]&name=%[^&]")   );

?>

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-10

Igor Feghali ¶

16 years ago


parses an input string with fixed field sizes that contains data with spaces:

<?php
$result = sscanf("  Vendor: My Vendo Model: Super Model Foo  Rev: 1234",  
                 '  Vendor: %8[ -~] Model: %16[ -~] Rev: %4c',
                 $vendor, $model, $rev);
?>

$vendor => My Vendo
$model => Super Model Foo 
$rev => 1234

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