How to remove duplicate characters from php string

Removal steps: 1. Use the str_split() function to convert the string into a character array, the syntax is "str_split(string,1)"; 2. Use the array_unique() function to remove duplicate values ​​in the character array , the syntax is "array_unique (character array)"; 3. Use the implode() function to restore the deduplicated character array to a string, the syntax is "implode (character array after deduplication)".

The operating environment of this tutorial: windows7 system, PHP version 8.1, DELL G3 computer

In php, you can use str_split(), The array_unique() and implode() functions are used to remove duplicate characters from strings.

Implementation steps:

Step 1: Use the str_split() function to convert the string into a character array

str_split( ) function can split the string into characters and pass them into the array as elements.

<?php  
header("content-type:text/html;charset=utf-8");
$str = "abcd123abcd321"; 
echo "原字符串：";
var_dump($str);
$arr=str_split($str,1);
echo "字符串转字符数组：";
var_dump($arr);
?>

Step 2: Use the array_unique() function to remove duplicate values ​​in the character array

array_unique() function is used to remove Remove duplicate values ​​in an array. If two or more array values ​​are the same, only the first value is retained and the other values ​​are removed.

$unique=array_unique($arr);
echo "字符数组去重：";
var_dump($unique);

Step 3: Use the implode() function to restore the deduplicated character array to a string

implode() The function returns a string composed of array elements.

$newstr=implode($unique);
echo "去重后的字符串：";
var_dump($newstr);

Explanation: The

implode() function can convert a one-dimensional array into a string. Its syntax format is as follows:

implode($glue, $array) 
//或者 
implode($array)

Among them, $glue is used to set a string, indicating that $glue is used to connect each element of the array together. By default, $glue is an empty string; $array is what needs to be converted. array.

Tip: The $glue parameter of the implode() function is optional and can be omitted.

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