How to remove before and after symbols in php

In PHP programming, we often need to operate strings. One common operation is to remove the symbols before and after the string, that is, to remove the symbols at the beginning and end of the string. This article will introduce several methods to achieve this operation.

Method 1:

Use the PHP built-in function trim() to remove whitespace characters at the beginning and end of the string, including spaces, tabs, newlines, etc. If we want to delete a specified character, we can pass the character to be deleted in the second parameter of the function. Only the beginning and end of the character will be deleted. The following is a sample code:

$str = "/hello world/";
$str = trim($str, "/");
echo $str;      // 输出 "hello world"

In the above code, use the trim() function to delete the slashes at the beginning and end of the string $str, and the output result is "hello world". It should be noted that if there are symbols at the beginning and end, they will only be deleted if these symbols are the same.

Method 2:

Use PHP’s built-in function substr() to intercept part of the string. We can intercept part of a string by passing the starting index and the number of characters to be intercepted. The following is a sample code:

$str = "/hello world/";
$str = substr($str, 1, -1);
echo $str;      // 输出 "hello world"

In the above code, use the substr() function to remove the slashes at the beginning and end of the string $str, and the output result is "hello world". It should be noted that the second parameter passed is a negative number, indicating the number of characters counting from back to front.

Method 3:

Use the PHP regular expression function preg_replace() to replace the part of the string that matches a certain pattern. We can use regular expressions to match the beginning and end symbols and then replace them with empty strings. The following is a sample code:

$str = "/hello world/";
$str = preg_replace('/(^\/*)|(\/*$)/', '', $str);
echo $str;      // 输出 "hello world"

In the above code, the preg_replace() function is used to remove the slashes at the beginning and end of the string $str, and the output result is "hello world". It should be noted that the "/" in the regular expression needs to be escaped.

To sum up, we have introduced three ways to remove surrounding and trailing symbols in PHP. These methods can be flexibly applied in different situations, and readers can choose the method that suits them according to actual needs.

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