How to remove repeated letters in string in php

php method to remove duplicate letters: first use the str_split() function to convert the string into a character array; then use the array_unique() function to remove duplicate values ​​in the array; finally use implode() to convert the processed Just convert the array into a string.

The operating environment of this tutorial: windows7 system, PHP7.1 version, DELL G3 computer

php removes duplicates in the string Letters

<?php
$str = &#39;abacade&#39;;
$array = str_split($str);
$str = implode(array_unique($array));
var_dump($str);
?>

Output:

## Related function description:

str_split() function splits a string into an array. The syntax is as follows:

str_split(string,length)

##Parameterstringlength

Description
Required. Specifies the string to be split.
Optional. Specifies the length of each array element. The default is 1.

array_unique()

Function is used to remove duplicate values ​​from an array. If two or more array values ​​are the same, only the first value is retained and the other values ​​are removed. Note: The retained array will retain the key type of the first array item.

Syntax

array_unique(array)

Parametersarraysortingtypeimplode() function returns a string composed of array elements. The syntax is as follows:

Description
Required. Specifies an array.
Optional. Specifies the sorting type. Possible values:	SORT_STRING - Default. Treat each item as a string. SORT_REGULAR - Sort each item in regular order (Standard ASCII, does not change type). SORT_NUMERIC - Treat each item as a number. SORT_LOCALE_STRING - Treat each item as a string, based on the current locale (can be changed via setlocale()).

implode(separator,array)

##ParameterDescriptionseparatorarray Recommended study: "PHP Video Tutorial

Optional. Specifies what is placed between array elements. Default is "" (empty string).
Required. Arrays to be combined into strings.

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