How to delete a string at a specified position in php

In PHP programming, string is one of the commonly used data types, and string operations are also frequently used. When operating strings, sometimes you need to delete the string at a specified position. This article will explore how to delete a string at a specified position in PHP.

1. Delete a single character at a specified position

If you need to delete a single character at a specified position in a string, you can use the substr_replace() function in PHP to replace the character at that position with Empty string "". The example is as follows:

$str = "Hello, world!";
$pos = 7;     //删除位置为 7 的字符 "w"
$str = substr_replace($str, "", $pos, 1);
echo $str;    //输出 "Hello, orld!"

In the above example, the substr_replace() function is used to replace the 1 character at position $pos in the string $str with the empty string "", thus achieving the deletion of a single character at the specified position. Character purpose.

2. Delete multiple characters at a specified position

If you need to delete multiple characters at a specified position in the string, you can use the substr_replace() function in a loop to repeatedly replace the characters. The characters at the position are replaced with the empty string "" to achieve the purpose of deleting multiple characters. The example is as follows:

$str = "This is a demo string.";
$start = 8;   //删除起始位置
$len = 4;     //删除字符长度
for ($i = $start; $i < $start + $len && $i < strlen($str); $i++) {
  $str = substr_replace($str, "", $i, 1);
}
echo $str;    //输出 "This is demo string."

In the above example, a for loop is used, starting from the starting position, by calling the substr_replace() function multiple times to replace the character at the specified position with the empty character "", thereby achieving deletion The purpose of multiple specified position characters.

3. Delete the string substring at the specified position

If you need to delete the string substring at a specified position in the string, you can use the substr() and substr_replace() functions together. , first find the substring at the specified position, and then replace it with the empty string "". The example is as follows:

$str = "hello, world!";
$substr = "world";  //要删除的子串
$start = strpos($str, $substr);  //子串起始位置
if ($start !== false) {
  $str = substr_replace($str, "", $start, strlen($substr));
}
echo $str;    //输出 "hello, !"

In the above example, the strpos() function is used to find the starting position of $substr in the string, and then the substr_replace() function is used to replace the substring at that position with "", thus achieving The purpose of deleting the string substring at the specified position.

4. Summary

This article mainly introduces how to delete a string at a specified position in PHP, including deleting a single character, deleting multiple characters and deleting a string substring. These tips are very practical in actual programming and I hope they will be helpful to PHP developers.

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