Remove Duplicate from String in PHP

remove duplicate from string in PHP

The shortest code would be:

$str = implode(',',array_unique(explode(',', $str)));

If it is the fastest... I don't know, it is probably faster then looping explicitly.

Reference: implode, array_unique, explode

How to remove duplicate letters in string in PHP

I tend to avoid regex when possible. Here, I'd just split all the letters into one big array and then use array_unique() to de-duplicate:

$unique = array_unique(str_split(implode('', $elem)));

That gives you an array of the unique characters, one character per array element. If you'd prefer those as a string, just implode the array:

$unique = implode('', array_unique(str_split(implode('', $elem))));

How to remove duplicate words from string using php?

I don't know if php have such function, but you can process it like this: live demo

$raw = 'AAA,BBB,aAA,BbB,AAA,BbB';
$string = implode(',', array_unique(explode(',', $raw)));

What's the best way to remove duplicates from a string in PHP (or any language)?

$arr = explode( " " , $string );
$arr = array_unique( $arr );
$string = implode(" " , $arr);

Remove duplicate from string

array_unique($string); //this is for an array,

$new_var = implode(',',array_unique(explode(',', $string))); //this is for a string

Removing duplicates from strings based on container [] {} ()

$input = '[1] {1} [2] {10} [3] [3] [4] {10} {100} [1] [5]';

$result = array_unique(explode(' ', $input));

Edit: Added two solutions for cases where there are no or multiple spaces.

The first solution preservers whitespaces as they are in the input string:

$result = array_reduce(
  str_split($input),
  function (array $carry, string $char) {
    return match ( $char ) {
      '(', '{', '[' => [ $carry[0], $char ],
      ')', '}', ']' => str_contains($carry[0], $carry[1] . $char)
                       ? $carry
                       : [ $carry[0] . $carry[1] . $char, '' ],
      ' '           => [ $carry[0] . ' ', '' ],
      default       => [ $carry[0], $carry[1] . $char ]
    };
  },
  [ '', '' ]
)[0];

The second one is variation, inserting one space between each item:

$result = array_reduce(
  str_split($input),
  function (array $carry, string $char) {
    return match ( $char ) {
      '(', '{', '[' => [ $carry[0], $char ],
      ')', '}', ']' => str_contains($carry[0], $carry[1] . $char)
                       ? $carry
                       : [ $carry[0] . ( $carry[0] === '' ? '' : ' ' ) . $carry[1] . $char, '' ],
      default       => [ $carry[0], $carry[1] . $char ]
    };
  },
  [ '', '' ]
)[0];

Compare duplicate words and remove them from a string in php

That's because array_unique() reduces duplicates to one value:

Takes an input array and returns a new array without duplicate values.

src

You need to loop the array first (though can imagine a lot of creative array_filter/array_walk stuff possibly):

$string = 'Super this is a test this is a test';

# first explode it
$arr = explode(' ', $string);

# get value count as var
$vals = array_count_values($arr);

foreach ($arr as $key => $word)
{
    # if count of word > 1, remove it
    if ($vals[$word] > 1) {
        unset($arr[$key]);
    }
}

# glue whats left together
echo implode(' ', $arr);

fiddle

And as a function for general project-use:

function rm_str_dupes(string $string, string $explodeDelimiter = '', string $implodeDelimiter = '')
{
    $arr = explode($explodeDelimiter, $string);
    $wordCount = array_count_values($arr);

    foreach ($arr as $key => $word)
    {
        if ($wordCount[$word] > 1) {
            unset($arr[$key]);
        }
    }

    return implode($implodeDelimiter, $arr);
}

# example usage
echo rm_str_dupes('Super this is a test this is a test');

php remove duplicates from string, if duplicate length is 4

Update

Based on comments from OP, the required regex is

/(^| )(.{4,}) (.*)\2/

This looks for a group of 4 or more characters preceded by either a space or the start of the line and followed by a space, some number of other characters and then the group repeated again. The regex is replaced by $1$2 $3 which effectively removes the duplicate string. A couple of examples:

$seoproducttitle = 'Apple MacBook Air MacBook Air - 13.3 inch - Intel Core i5-8e - MRE82N/A';
echo preg_replace('/(^| )(.{4,}) (.*)\2/', "$1$2 $3", $seoproducttitle) . "\n";
$seoproducttitle = 'HP Chromebook 11 G5 EE Chromebook - 11.6 inch - Intel® Intel® Celeron® - 4LT18EA#ABH 4LT18EA#ABH';
echo preg_replace('/(^| )(.{4,}) (.*)\2/', "$1$2 $3", $seoproducttitle) . "\n";

Output:

Apple MacBook Air - 13.3 inch - Intel Core i5-8e - MRE82N/A Array
HP Chromebook 11 G5 EE - 11.6 inch - Intel® Celeron® - 4LT18EA#ABH

Updated demo on 3v4l.org

Original Answer

You could use this regex:

\b([^ ]{4,})( |$)(.*)\1

It looks for a group of 4 or more non-blank characters, followed by a space or end-of-string, followed by some number of other characters and then the first group repeated. The regex is replaced by $1$3 which effectively removes the duplicate string. e.g.

$seoproducttitle = 'HP Chromebook 11 G5 EE Chromebook - 11.6 inch - Intel® Intel® Celeron® - 4LT18EA#ABH 4LT18EA#ABH';
echo preg_replace('/\b([^ ]{4,})( |$)(.*)\1/', "$1$3", $seoproducttitle);

Output:

HP Chromebook11 G5 EE - 11.6 inch - Intel® Celeron® - 4LT18EA#ABH

Demo on 3v4l.org

How to remove duplicates from a PHP string separated by X?

The file is read into an array with file. With array_map and preg_replace the spaces and the X are removed from each line. array_unique then removes the duplicate entries.

$array = file('input.txt',FILE_IGNORE_NEW_LINES | FILE_SKIP_EMPTY_LINES);
$array = array_map(function($v){return preg_replace('/ +X;/',';',$v);}, $array);
$array = array_unique($array);

The result is an array.

array (
  0 => "13:BOOT2700;27",
  4 => "13:BOXER1136;11.36",
  5 => "13:BOXER1364;13.64",
  6 => "13:BOXER1591;15.91",
  7 => "13:BOXER909;9.09",
)

If a file is required as a result, the array can be converted into a string with implode and written to a file with file_put_contents.

$str = implode("\r\n",$array);
file_put_contents('input.csv', $str);