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phpstringduplicatespreg-replacecpu-word
kaneyip
kaneyip

Reputation: 1267

PHP preg replace duplicate words in string if more than three

I'm new to PHP. I would like to replace a string with specific duplicate words if more than three into two like below?

$wordToCheck = "abc";
$string = "abc abc abc abc Hello World abc abc abc My name is abc"

The result will be:

$outString = "abc abc Hello World abc abc My name is abc"

How can I do this in PHP?

Thanks in advance.

Upvotes: 0

Views: 819

Answers (3)

FuzzyTree
FuzzyTree

Reputation: 32392

$string = "abc abc abc abc Hello World abc abc abc My name is abc";
print preg_replace("/abc abc abc( abc)*/","abc abc",$string);

Upvotes: 2

Casimir et Hippolyte
Casimir et Hippolyte

Reputation: 89557

You can replace more than 2 consecutive same word with the following pattern that uses a backreference to the capture group 1 (i.e. \1):

$pattern = '~\b(\w+) \1 \K\1(?: \1)*\b ?~';
$replacement = '';

$str = preg_replace($pattern, $replacement, $str);

Note that since the \K removes all that have been matched on the left from the match result, the two first occurences are not replaced.

online demo

Upvotes: 2

Bob Brown
Bob Brown

Reputation: 1502

You could use PHP's explode like this: $wordArray = explode ( " ", $string);

$wordArray will now contain one element for each space-delimited word in the original string.

You could then say something like:

$i = 0;
while ($wordArray[$i] == $wordToCheck) {
    $i++;
}

At that point, $i will tell you how many occurrences of $wordToCheck are at the beginning of the string. After that, PHP's array_shift will remove elements from the front of the array, and, after you've shifted out enough words to leave only two, the implode function will turn the array back into a string.

Edited to add: I have not used regular expressions; I'm not sure how to do that, and I am sure you don't need to.

Edited again: This has been tested, and will work even if the first "word" of the string is not $wordToCheck:

<?php
$wordToCheck = "abc";
$string = "abc abc abc abc Hello World abc abc abc My name is abc";
$wordArray = explode ( " ", $string);
$i = 0;
while ($wordArray[$i] == $wordToCheck) {
    $i++;
}
for ($j=0; $j < $i-2; $j++) {
   array_shift($wordArray);
}
$string = implode(" ",$wordArray);
echo $string;
?>

Upvotes: 0

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