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The `substr()` function in PHP is used to extract a portion of a string. It returns a part of the given string starting from a specified position and optionally with a specified length. The function is available in both PHP 8.1 and PHP 8.2.
Here’s the syntax of the `substr()` function:
substr(string $string, int $start, ?int $length = null): string|false
1. `$string`: The input string from which to extract the substring.
2. `$start`: The starting position for extraction. If negative, it starts counting from the end of the string.
3. `$length` (optional): The length of the extracted substring. If omitted, the substring will extend to the end of the string.
If successful, `substr()` returns the extracted substring as a string. If an error occurs, such as invalid input parameters, it returns `false`.
Here’s an example of how to use `substr()`:
<?php // Original string $string = "Hello, World!"; // Extract a substring starting from position 7 $substring1 = substr($string, 7); // Extract a substring starting from position 7 with length 5 $substring2 = substr($string, 7, 5); // Output the extracted substrings echo "Substring 1: $substring1<br>"; echo "Substring 2: $substring2"; ?>
In this example:
1. `$substring1` extracts the substring starting from position 7 (`W`), and it continues to the end of the string.
2. `$substring2` extracts the substring starting from position 7 (`W`) with a length of 5 characters.
The output will be:
Substring 1: World! Substring 2: World
These examples demonstrate how to use `substr()` to extract substrings from a string in PHP 8.1 and PHP 8.2.