Truncate String

[eluser]sophistry[/eluser]
I wrote up a test file. it is at http://codeigniter.com/wiki/String_Parsing_Test_Code/.

conclusion:
------------------
substr() approach is best overall - it is fast with small strings (preg_replace is the fastest).
substr() stays fast no matter how large the input string gets (the other techniques slow with progressively longer strings).

here are the four approaches i tested:

Code:

function preg_rep_cut($in,$split_at_regex)
{
    return preg_replace($split_at_regex, '', $in, 1);
}

function preg_split_pre_cut($in,$split_at_regex)
{
    return current(preg_split($split_at_regex, $in, 2));
}

function substr_cut($in, $splitat)
{
    $out = (substr($in, 0, strpos($in, $splitat)));
    return $out?$out:$in;
}

function explode_cut($in, $splitat)
{
    return current(explode($splitat, $in, 2));
}

sample output from the code:

Code:

Array
(
    [/\<\|more\|\>.*+/si] => Array
        (
            [0] => 0.0064
            [10] => 0.0072
            [200] => 0.0086
            [400] => 0.0087
            [800] => 0.0091
            [1600] => 0.0385
            [3200] => 0.1111
        )

    [/\<\|more\|\>/s] => Array
        (
            [0] => 0.0066
            [10] => 0.0068
            [200] => 0.0095
            [400] => 0.0095
            [800] => 0.0098
            [1600] => 0.0105
            [3200] => 0.0755
        )

    [substr] => Array
        (
            [0] => 0.0071
            [10] => 0.0073
            [200] => 0.009
            [400] => 0.0089
            [800] => 0.009
            [1600] => 0.009
            [3200] => 0.009
        )

    [explode] => Array
        (
            [0] => 0.006
            [10] => 0.0064
            [200] => 0.0107
            [400] => 0.0132
            [800] => 0.0138
            [1600] => 0.0141
            [3200] => 0.0809
        )

)
Array
(
    [substr] => 0.00847142857143
    [/\<\|more\|\>/s] => 0.0183142857143
    [explode] => 0.0207285714286
    [/\<\|more\|\>.*+/si] => 0.0270857142857
)

enjoy. :coolsmile: