Trim symbol and decimal value from currency string

I have currency input strings like these.

• $50 …I only need 50
• $60.59 …I only need 60, need to remove $ and .59
• €360 …I only need 360
• €36.99 …I only need 36, need to remove € and .99
• £900 …I only need 900
• £90.99 …I only need 90

In other words, I need to remove all currency symbols from the start of the string and I only need the integer value — the decimal values can be cut off.

Answer

I would recommend not using a regular expression, as it’s overkill for this scenario.

$str = (int)ltrim($str, '$£€');

this is all you need.

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Performance vs Regex

I ran the above test through a script to see what the time difference is between my answer and using a RegEx, and on average the RegEx solution was ~20% slower.

<?php
function funcA($a) {
    echo (int)ltrim($a, '$£€');
};
function funcB($a) {
    echo preg_replace('/^.*?([0-9]+).*$/', '$1', $a);
};
//setup (only run once):
function changeDataA() {}
function changeDataB() {}

$loops = 50000;
$timeA = 0.0;
$timeB = 0.0;
$prefix =  str_split('€$€');

ob_start();
for($i=0; $i<$loops; ++$i) {
    $a = $prefix[rand(0,2)] . rand(1,999) . '.' . rand(10,99);

    $start = microtime(1);
    funcA($a);
    $timeA += microtime(1) - $start;

    $start = microtime(1);
    funcB($a);
    $timeB += microtime(1) - $start;
}
ob_end_clean();

$timeA = round(1000000 * ($timeA / $loops), 3);
$timeB = round(1000000 * ($timeB / $loops), 3);

echo "
TimeA averaged $timeA microseconds
TimeB averaged $timeB microseconds
";

Timings vary depending on system load, so times should be considered only relative to each other, not compared between executions. Also this isn’t a perfect script for performance benchmarking, there are outside influences that can affect these results, but this gives a general idea.

TimeA averaged 5.976 microseconds
TimeB averaged 6.831 microseconds