sscanf

Victor (2012-09-23 22:24:24)

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

nmmm at nmmm dot nu (2011-11-23 05:11:03)

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=%[^&]")   );
?>

Igor Feghali (2008-10-22 10:56:40)

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

leg (2008-08-13 09:20:50)

@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!

--==[FReeZ]==-- (2008-05-27 13:59:39)

sscanf() in PHP also supports the more advanced patterns like in C++.
That means you can use it a lot more, after readining the details from http://www.cplusplus.com/reference/clibrary/cstdio/sscanf.html
Example usage:
$date = 'january-2008';
sscanf($date, '%[a-z]-%d', $month, $year);
printf('Parsed values: "%s", "%d"', $month, $year);
// Outputs Parsed values: "january", "2008"

mikewillitsgmail.com (2008-03-15 11:13:03)

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

Hayley Watson (2007-08-13 20:38:25)

Just to note something not explicitly mentioned in the documentation.
sscanf() matches as much of the passed string as it can against the format. If it gets part way through and discovers that the next part of the string fails to match the format it gives up; it will return the parts that it did match, and NULL for the remainder.

Rodrigo Araújo (2006-10-12 13:02:08)

Important warning about the last note by "anonymouse" (quoting):
----------------------------------------------------------------------
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"
----------------------------------------------------------------------
This won't do what you think. You have the ^ and $ characters inside square brackets: $text will be empty if $string_to_parse contains for example "123 $".
What that pattern really means is: match an signed integer, followed by a whitespace, followed by a string *NOT* containing a dollar sign, followed by an 's'.
To do what you want i'm afraid you really must use ereg. Scanf is *not* a regular expression parser. It was designed to be used in plain C, where you don't have arbitrary length strings natively. Also, in scanf patterns you don't have an equivalent to matching the beginning/end of string, like you have with ^ and $ in regular expressions.
In PHP, you should use something like:
if (ereg('^([+-]?[0-9]+) (.+)$', $string_to_parse, $regs)) {
$num = $regs[1];
$text = $regs[2];
}
This regular expression assumes you want a signed integer at the beginning, and you don't mind if it starts with 0 when it is non-zero, e.g. 0123, +0321 or -0456 is also valid.

anonymouse (2006-08-01 21:38:58)

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"

skeltoac (2006-03-22 20:28:35)

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']
);
?>

Fuzzmaster (2005-09-23 07:14:07)

Building a better Phone Format.  This function, a variation of prev. posts (in theory):

Should stip all non-numeric characters.
Treat partial numbers as extensions.
Treat 8 - 9 digit numbers as phone+ext.

Be kind I'm a newbie.

<?php 

    // ##### Format String as Phone Number
    Function formatPH($ph)
          {
           $ph = ereg_replace ('[^0-9]+', '', $ph); // ##### Strip all Non-Numeric Characters
           $phlen = strlen($ph);
           switch (TRUE)
             {
              case ($phlen < 7):
                $ext = $ph;
                break;
              case ($phlen == 7):
                sscanf($ph, "%3s%4s", $pfx, $exc);
                break;
              case ($phlen > 7 AND $phlen < 10):
                sscanf($ph, "%3s%4s%s", $pfx, $exc, $ext);
                break;
              case ($phlen == 10):
                sscanf($ph, "%3s%3s%4s", $area, $pfx, $exc);
                break;
              case ($phlen == 11):
                sscanf($ph, "%1s%3s%3s%4s", $cty, $area, $pfx, $exc);
                break;
              case ($phlen > 11):
                sscanf($ph, "%1s%3s%3s%4s%s", $cty, $area, $pfx, $exc, $ext);
                break;
             }
           $out = '';
           $out .= isset($cty) ? $cty.' ' : '';
           $out .= isset($area) ? '('.$area.') ' : '';
           $out .= isset($pfx) ? $pfx.' - ' : '';
           $out .= isset($exc) ? $exc.' ' : '';
           $out .= isset($ext) ? 'x'.$ext : '';
           return $out;
          }

?>

Brainiac361 (2005-08-22 13:49:48)

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.

joshmckenneyATgmailDOT(0{ (2005-07-14 15:21:13)

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;
}

Vincent Jansen (2005-06-16 01:04:06)

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");
?>

codeslinger at compsalot dot com (2005-02-06 06:03:33)

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.

steve (atsign) rapaport *fullstop* com (2004-09-18 16:27:01)

The classic example 
<?php
list($month, $day, $year) = sscanf($mandate, "%s %d %d");
?>

works fine if you already know the variable names you want to fill, and the format string you want to fill them with.  If you want both of those to be dynamically configurable (as in reading a file with a flexible format), you may have a use for this code:

Assumes your variables are listed in the variable 
$varstr = "var1, var2, var3"  
(you don't know what the variable names will be, 
 perhaps they're a subset of a long list of valid ones)

Assumes your input line is in $line, and your sscanf spec is in $spec.  Both of these may also be in your input.

Integrity checks omitted for clarity.

<?php
        $vars = explode(',', $varstr);

        $values = @sscanf($line, $spec);
        // Do input integrity checks

        foreach ($vars as $var) {
            $var = trim($var);
            $next = each($values);
            $$var = $next['value'];
            if ($$var) $result_array[$var] = $$var; 
        }
?>

This took me some time to write successfully, so I'm including it for posterity.  Non-obvious is the use of
$next.

Cheers,

Steve

marcus at synchromedia dot co dot uk (2003-03-24 09:38:31)

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.

sbarnum.pointsystems@com (2003-02-19 13:29:15)

This is a better phone format function than the one above, handles leading zeroes correctly, by using the "%s" instead of "%d" argument to sscanf(). Again, this function assumes that the input has been stripped of all non-integer values.
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)
sscanf($phone, "%3s%3s%4s%s", $area, $prefix, $exchange, $extension);
else
return "unknown phone format: $phone";
$out = "";
$out .= isset($area) ? '(' . $area . ') ' : "";
$out .= $prefix . '-' . $exchange;
$out .= isset($extension) ? ' x' . $extension : "";
return $out;
}

sbarnum.pointsystems@com (2002-11-19 19:21:41)

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;
}

jon at fuck dot org (2002-09-13 11:27:53)

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');

jamesDOTwatsonATrealismstudiosDOTcom (2002-07-10 12:31:30)

You're making a common mistake in believing that sscanf (and the whole scanf family) are more intelligent than they really are, sscanf always starts checking from the first character of the string, the first character that doesn't match the format string causes it to bail out early, if you want to match later in the string you'll have to do something like this:
sscanf(strstr($lit[$x],"Vol."),"Vol. %d",&$vol[$x]);
(check the docs on strstr if you're unsure of how it works)
or if you want you can add some simple error correction
$temp=strstr($lit[$x],"Vol.");
if ($temp)
sscanf($temp,"Vol. %d",&$vol[$x]);
else
$vol[$x]=$default_vol;

elgabos at umail dot ucsb dot edu (2002-02-27 03:38:53)

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

narainsbrain at yahoo dot com (2001-10-14 03:25:24)

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().

owenh at halo5 dot com (2000-11-28 04:21:12)

<?php list($phone11, $phone12, $phone13) = sscanf($arow[9],"(%d) %d-%d"); ?>

If thoes variables dont have data in them it seems to cause segfaults on apache.  ( just to save you some trouble shooting time here is my fix: 
<?php sscanf($arow[9],"(%d) %d-%d", &$phone11,&$phone12, &$phone13); ?>

clcollie at mindspring dot com (2000-09-12 04:59:19)

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.