PHP returns the string from the last occurrence of a string to the end of another string

In PHP, if you need to return a substring from the last occurrence of a string to the end of another string, you can use the built-in function strrchr() to achieve this. The strrchr() function will find the last occurrence of the specified string in the target string and return the part of the string to the end. Using this function, you can easily intercept the required string paragraph and improve the efficiency and readability of the code. Below we will introduce in detail how to use the strrchr() function in PHP to achieve this function.

Get the string from the last occurrence of the string to the end in PHP

question: How to use php to get the substring of a string starting from the last occurrence of another string to the end?

solution:

There are two main methods in PHP to get the substring from the last occurrence of a string to the end:

1. Use strrpos() function

strrpos() The function returns the position of the last occurrence of a string in another string. We can use this position and the substr() function to extract the substring:

<?php
$string = "Hello World, welcome to the world of PHP!";
$substring = "world";

// Get the position of the last occurrence of "world" in $string
$pos = strrpos($string, $substring);

// If "world" exists in the string, extract the substring
if ($pos !== false) {
$subString = substr($string, $pos);
echo $subString; // Output "world of PHP!"
} else {
echo "Substring not found.";
}
?>

2. Use preg_match() function

preg_match() The function can perform a regular expression search. We can use regular expressions to match the last occurrence of a substring in a string:

<?php
$string = "Hello World, welcome to the world of PHP!";
$pattern = "/.*$substring$/";

// Perform a regular expression search and get matches
preg_match($pattern, $string, $matches);

// If a match is found, extract the substring
if (isset($matches[0])) {
$subString = $matches[0];
echo $subString; // Output "world of PHP!"
} else {
echo "Substring not found.";
}
?>

Performance considerations:

The

strrpos() function generally performs better than the preg_match() function because it does not need to perform regular expression matching. However, the preg_match() function provides more flexible search options.

Best Practices:

• Make sure the substring exists in the string, otherwise it may produce unexpected results.
• Use === or !== operators to strictly compare the values ​​of $pos to avoid mistaking 0 is false.
• Consider using the preg_replace() function to replace substrings in a string.

Other methods:

In addition to the above methods, there are other methods to obtain the substring from the last occurrence of the string to the end, for example:

• Use string slicing ($string[$pos:])
• Use array_slice() function
• Use custom functions or third-party libraries

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