match two strings and compare each letter in php

Question

I googled this question I can't to find the exact solution...

I have 2 variables...

$s1 = "ABC"; //or "BC"
$s2 = "BC"; //or "Bangalore"

I have to compare $s1 and $s2 and give the output as letters which is not present in $s2 eg : "A" // or"C"

Like that I have to compare $s2 and $s1 and give the output as letters which is not present in $s1 eg : null // or"angalore"

What I tried.. I spit the strings to array... Using nested for loop to find the non matched letters... I wrote code more than 35 lines.. But no result :( Please help me ......

Do you really want to compare single letters? In the example you give the result could never be "Angalore", because it would only return single letters. — eevaa, Jan 04 '14 at 13:29
let's say ... "ABC" and "Bangalore" are Sets (Set theory of Math), then you want "ABC" minus "Bangalore" and "Bangalore" minus "ABC". is it what you want? — Tun Zarni Kyaw, Jan 04 '14 at 13:31
http://stackoverflow.com/questions/7475437/find-first-character-that-is-different-between-two-strings — , Jan 04 '14 at 13:34
`$s1 = "ABC";` or `$s1 = "BC"` just i gave two value for example.... please take any one `$s1 = "ABC";` `$s2 = "BC";` or `$s1 = "BC";` `$s2 = "Bangalore";` — rynhe, Jan 04 '14 at 13:36

score 3 · Answer 1 · answered Jan 04 '14 at 13:47

3

echo str_ireplace(str_split($s2), "", $s1); // output: A

answered Jan 04 '14 at 13:47

revo

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Dont know why this was down-voted - simplest and most concise answer! – GrahamTheDev Jan 04 '14 at 13:49
haha I am commenting saying why the down-vote - it was me! I must have slipped - like I said best answer – GrahamTheDev Jan 04 '14 at 13:51

score 2 · Answer 2 · answered Jan 04 '14 at 13:32

2

You can use array_diff() here:

function str_compare($str1, $str2)
{
    $str1chars = str_split($str1);
    $str2chars = str_split($str2);
    $diff = array_diff($str1chars, $str2chars)
    return implode($diff);
}

By calling the function as follows:

$diffchars = str_compare('ABC', 'BC');

You will receive a string containing the characters that do not appear in both strings. In this example, it'll be A, because that character appears in $str1, but not in $str2.

answered Jan 04 '14 at 13:32

BenM

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Wow, your `for` loop for creating the array of characters quickly changed to `str_split()` ;) – Amal Murali Jan 04 '14 at 13:36
@AmalMurali indeed it did. One of those moments where I completely forgot about `str_split()`! – BenM Jan 04 '14 at 13:37

score 2 · Answer 3 · edited Jan 04 '14 at 13:39

2

Use array_diff():

function str_diff($str1, $str2) {
    $arr1 = str_split($str1);
    $arr2 = str_split($str2);
    $diff = array_diff($arr1, $arr2);
    return implode($diff);
}

Usage:

echo str_diff('BC', 'Bangalore'); // => C
echo str_diff('ABC', 'BC');       // => A

edited Jan 04 '14 at 13:39

BenM

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answered Jan 04 '14 at 13:32

Amal Murali

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@TunZarniKyaw he had the return values reversed. Updated. – BenM Jan 04 '14 at 13:39
oops, i didn't downvote, just wanted to point out what is incorrect in comment – Tun Zarni Kyaw Jan 04 '14 at 13:59

score 2 · Answer 4 · answered Jan 04 '14 at 13:33

2

You can use str_split and array_diff like :

<?php
$s1 = 'abcedf';
$s2 = 'xzcedf5460gf';

print_r(array_diff(str_split($s1), str_split($s2)));

answered Jan 04 '14 at 13:33

OneOfOne

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score 2 · Answer 5 · answered Jan 04 '14 at 13:42

Ok to do this

$str1s = "abc";
$str2s = "BCd";


function findNot($str1, $str2, $asArray = false){

    $returnValue = array_diff(array_unique(str_split(strtolower($str1))), array_unique(str_split(strtolower($str2))));

    if($asArray == false){

        return implode($returnValue);

    }else{

        return $returnValue;

    }

}

echo findNot($str1s, $str2s); //gives a string
echo findNot($str1s, $str2s, true); //gives array of characters

This allows you to return as either array or string.

match two strings and compare each letter in php

5 Answers5

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