How efficient is PHP's substr?

Posted by zildjohn01 on Stack Overflow See other posts from Stack Overflow or by zildjohn01
Published on 2010-05-11T17:51:30Z Indexed on 2010/05/11 18:14 UTC
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Filed under:

php

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substr

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optimization

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memory-usage

I'm writing a parser in PHP which must be able to handle large in-memory strings, so this is a somewhat important issue. (ie, please don't "premature optimize" flame me, please)

How does the substr function work? Does it make a second copy of the string data in memory, or does it reference the original? Should I worry about calling, for example, $str = substr($str, 1); in a loop?

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