Does PHP str_replace have a greater than 13 character limit?

Question

This works up until the 13th character is hit. Once the str_ireplace hits "a" in the cyper array, the str_ireplace stops working.

Is there a limit to how big the array can be? Keep in mind if type "abgf" i get "nots", but if I type "abgrf" when I should get "notes" I get "notrs". Racked my brain cant figure it out.

$_cypher = array("n","o","p","q","r","s","t","u","v","w","x","y","z","a","b","c","d","e","f","g","h","i","j","k","l","m");

$_needle = array("a","b","c","d","e","f","g","h","i","j","k","l","m","n","o","p","q","r","s","t","u","v","w","x","y","z");


$_decryptedText = str_ireplace($_cypher, $_needle, $_text);
echo $_decryptedText;

Help?

http://php.net/manual/en/function.str-rot13.php – Brad Oct 14 '11 at 18:05 — Brad, Oct 14 '11 at 18:05

hakre · Accepted Answer · 2011-10-14T18:21:05.090

5

Use strtr^Docs:

$_text = 'abgrf';

$translate = array_combine($_cypher, $_needle);

$_decryptedText = strtr($_text, $translate);

echo $_decryptedText; # notes

Demo

But, was there something I was doing wrong?

It will replace each pair, one pair after the other on the already replaced string. So if you replace a character that you replace again, this can happen:

    r -> e   e -> r
abgrf -> notes -> notrs

Your e-replacement comes after your r-replacement.

edited Oct 14 '11 at 18:21

answered Oct 14 '11 at 18:08

hakre

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Ah. So like @ircmaxell said, it's doing a circular replacement. Is other than using str_rot13 is there a way to complete the task as I have it? – user-44651 Oct 14 '11 at 18:16
@Firemarble: As written `strtr`. I added an example. – hakre Oct 14 '11 at 18:19

score 2 · Answer 2 · answered Oct 14 '11 at 18:13

Take a peak at the docs for str_replace. Namely the following line:

Because str_replace() replaces left to right, it might replace a previously inserted value when doing multiple replacements. See also the examples in this document.

So it's working as told. It's just doing a circular replacement (n -> a, then a -> n).

score 1 · Answer 3 · answered Oct 14 '11 at 18:04

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Use str_rot13

answered Oct 14 '11 at 18:04

nachito

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Thanks, that works. But, was there something I was doing wrong? – user-44651 Oct 14 '11 at 18:07

score 0 · Answer 4 · answered Oct 14 '11 at 18:09

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although it appears to be a straight rot13, if it is not, another option is to use strtr(). You provide a string and an array of replacement pairs and get the resulting translation back.

answered Oct 14 '11 at 18:09

Jonathan Kuhn

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Does PHP str_replace have a greater than 13 character limit?

4 Answers4

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