CODEWITHSUNDEEP
phpregexstringreplace
nortonuser
nortonuser

Reputation: 215

Replace character from string if only previous or next character not containing the same character

I have a set of string like this:

$string1 = 'man_city/man_united'; //it will  be replaced
$string2 = 'liverpool///arsenal'; //it will not be replaced
$string3 = 'chelsea//spurs'; //it will  not be replaced
$string4 = 'leicester/sunderland'; //it will be replaced

i want to replace the '/' character from string with '/' but only if next or previous character from '/' character not containing '/' too.

if i use str_replace like this, it won't work:

$name1 = str_replace("/","\/",$string1);
$name2 = str_replace("/","\/",$string2);
...
//output
$name1 = 'man_city\/man_united';
$name2 = 'liverpool\/\/\/arsenal';
...
//desired output
$name1 = 'man_city\/man_united';
$name2 = 'liverpool///arsenal';
...

Upvotes: 3

Views: 1764

Answers (4)

Wiktor Stribiżew
Wiktor Stribiżew

Reputation: 626961

You may use

'~(?<!/)/(?!/)~'

See the regex demo.

The (?<!/) negative lookbehind will fail the match if there is a / before / and (?!/) negative lookahead will fail the match if there is a / after /.

PHP demo:

$re = '~(?<!/)/(?!/)~';
$str = "man_city/man_united\nliverpool///arsenal\nchelsea//spurs\nleicester/sunderland";
$result = preg_replace($re, "\\/", $str);
echo $result;

Output:

man_city\/man_united
liverpool///arsenal
chelsea//spurs
leicester\/sunderland

Upvotes: 4

mrzasa
mrzasa

Reputation: 23327

You can try with negative lookarounds:

$name = preg_replace("/(?<!\/)\/(?!\/)/","\/",$string1);

Demo

Explanation:

(?<!\/)\/(?!\/)
  • (?<!\/) negative lookbehind - matches a place in the string that is nontpreceded with /
  • \/ matches '/'
  • (?!\/) negative lookahead - matches place in the string not followed by / `

Upvotes: 0

Ashish Tiwari
Ashish Tiwari

Reputation: 2277

I thinks this can help you:

<?php
$string1 = 'man_city/man_united'; //it will  be replaced

if(!substr_count($string1, '//')){
   $string1 = str_replace('/','#',$string1); //Do replace accordingly 
}

echo $string1;

Upvotes: 0

Dormilich
Dormilich

Reputation: 927

In this case it's easier to use a regular expression (=> preg_replace()).

e.g. preg_replace(#/+#, '/', $str)

Upvotes: 0

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