Library Functions

Library Functions
Library functions in PHP refer to built-in functions that are part of the PHP language and provide a wide range of functionality to developers. These functions are included in PHP’s standard library, and they cover tasks such as string manipulation, array handling, file operations, database access, mathematical calculations, date and time manipulation, and much more.
Library functions are an essential part of PHP development because they allow developers to perform common tasks efficiently without having to write custom code for every operation. Here are some examples of commonly used PHP library functions:
1.String Functions:
(a)strlen(): Returns the length of a string.
(b)strpos(): Finds the position of the first occurrence of a substring in a string.
(c)str_replace(): Replaces all occurrences of a substring with another substring in a string.
2.Array Functions:
(a)count(): Returns the number of elements in an array.
(b)array_push(): Adds one or more elements to the end of an array.
(c)array_pop(): Removes and returns the last element of an array.
3.File Functions:
(a)file_get_contents(): Reads the contents of a file into a string.
(b)file_put_contents(): Writes a string to a file.
(c)fopen(), fclose(), fwrite(): Functions for low-level file handling.
4.Database Functions:
(a)mysqli_connect(), mysqli_query(), mysqli_fetch_assoc(): Functions for MySQL database interactions.
(b)PDO: PHP Data Objects for working with various database systems.
5.Math Functions:
(a)abs(): Returns the absolute value of a number.
(b)sqrt(): Returns the square root of a number.
(c)rand(): Generates a random number.
6.Date and Time Functions:
(a)date(): Formats a date and time.
(b)strtotime(): Parses a time string into a Unix timestamp.
(c)time(): Returns the current Unix timestamp.
7.Regular Expression Functions:
(a)preg_match(): Performs a regular expression match.
(b)preg_replace(): Performs a regular expression search and replace.
8.JSON Functions:
(a)json_encode(): Converts a PHP value to a JSON string.
(b)json_decode(): Decodes a JSON string into a PHP value.
9.Session and Cookie Functions:
(a)session_start(): Starts a session.
(b)setcookie(): Sets a cookie.
These are just a few examples, and PHP provides many more library functions that cater to various programming needs. You can find the complete list of PHP library functions in the official PHP documentation, which is a valuable resource for PHP developers.