string help

[esthera]

I have a string that usually has 2 letters and then a number (anywhere from 1 -1000)

I want to be able to parse out the 2 letters and then the number.

This is easy in the case where I have the 2 letters But sometimes there is only one letter or no letters --how can I parse it then?
I want to separate the letters from the numbers.

[LarsLai]

hi!
I think with regular expressions you can parse for letters and numbers.
There are many tutorials about this, e.g. one on this site:
http://www.phpbuilder.com/columns/dario19990616.php3
cheers

[Installer]

function separate_letters_from_number($str) 
{
    $num = '';
    $ltr = '';
    for ($i = 0; $i < strlen($str); $i++) {
        if (is_numeric($str{$i})) {
            $num .= $str{$i};
        } else {
            $ltr .= $str{$i};
        }
    }
    $ret = array($num, $ltr);
    return $ret;
}

$test = array('ab101', 'c9999', '810', 'cd', 'c558');
foreach ($test as $value) {
    $array = separate_letters_from_number($value);
    echo $value . '<br />';
    echo $array[0] . '<br />';
    echo $array[1] . '<br />';
    echo '<br />';
}

[paulnaj]

Hi esthera,

Lars is right, regexps are really powerful ... try to get to grips with them.

But, in any case, it's a good policy to try to list all the possible alternative strings, to get a handle on what's going on.

From what you've said, this list seems to be ...

XXNNNN
XXNNN
XXNN
XXN
XX

... where X is a character and N a digit.

Now when you say 'parse' I assume you mean 'extract the two pieces of information'.

Suppose $code contains the string ...

<?php
$characters = substr($code, 0, 2);
$digits = substr($code, 2); 

if($digits === ''){ // Check if empty
    echo 'No numbers';
} else {
    $digits = 0 + $digits; // Convert to number
}?>[\PHP]

Paul. ;)

[esthera]

actually it is a string of 0 to 2 letters and then 1 to 4 numbers.

I tried installers function to separate but got a parse error on line:
echo $array[0] . '<br />';

[Installer]

Did you copy and paste the code or retype the whole thing? If you retyped it (as you apparently did), you made a typo. Otherwise, there's no parse error there. (And the code works.)

btw, I post the code in the hopes that you will "deconstruct" it to see how it works. The basic string functions in PHP are very powerful. Using them and logic, you can solve most string manipulation functions. Once you have that basic use learned, then, for more advanced problems (this is not one), learning regular expressions is in order.