How to remove identical items from a string in php

Removal method: 1. Use str_split() to convert the string into a character array, the syntax is "str_split(string)"; 2. Use array_unique() or array_flip() to remove the same items of the array, the syntax is " array_unique(character array)" or "array_flip(array_flip(character array))"; 3. Use implode() to convert the deduplicated array into a string, the syntax is "implode("", deduplicated array)".

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

In PHP, you want to remove strings Identical items (repeating characters) can use arrays.

Implementation idea:

• Convert the string into a character array

• Remove the character array The same items

• Convert the deduplicated array to a string

Method 1: str_split() array_unique() implode ()

• Use the str_split() function to convert the string into a character array. One character is an array element

• Use array_unique () function to deduplicate the array

• Use the implode() function to convert the deduplicated array into a string
  

<?php
header(&#39;content-type:text/html;charset=utf-8&#39;);   
$str = "1.2.3.1.2.3.4";
echo "原字符串：".$str."<br><br>";

$arr=str_split($str);
echo "字符数组：";
var_dump($arr);

$newArr=array_unique($arr);
echo "去重后的数组：";
var_dump($newArr);
$newStr=implode("",$newArr);
echo "去重后的字符串：".$newStr;
?>

Method 2: str_split() array_flip() implode()

• Use the str_split() function to convert the string into characters Array, one character is an array element

• Use the array_flip() function twice to deduplicate the array

  array_flip is a function that reverses the keys and values ​​of the array. It has A feature is that if two values ​​in the array are the same, then the last key and value will be retained after inversion. Using this feature, we use it to indirectly implement deduplication of the array
  

• Use the implode() function to convert the deduplicated array into a string

<?php
header(&#39;content-type:text/html;charset=utf-8&#39;);   
$str = "12hello13";
echo "原字符串：".$str."<br><br>";

$arr=str_split($str);
echo "字符数组：";
var_dump($arr);

$newArr=array_flip(array_flip($arr));
echo "去重后的数组：";
var_dump($newArr);
$newStr=implode("",$newArr);
echo "去重后的字符串：".$newStr;
?>

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