What is PHP Functions?
Functions are blocks of reusable code that perform specific tasks. They are an essential part of any programming language, including PHP. PHP provides a large number of built-in functions for a variety of tasks, such as string manipulation, date and time processing, and file I/O. You can also create your own functions to encapsulate reusable code and make your programs more modular and easier to maintain.
Here are some of the most common types of PHP functions:
- String Functions:
- strlen(): Returns the length of a string.
- str_replace(): Replaces all occurrences of a search string with a replacement string.
- strpos(): Finds the position of the first occurrence of a substring in a string.
2. Array Functions:
- count(): Counts the number of elements in an array.
- array_push(): Pushes one or more elements onto the end of an array.
- array_pop(): Pops the element off the end of an array.
3. Math Functions:
- abs(): Returns the absolute value of a number.
- round(): Rounds a floating-point number to the nearest integer.
- rand(): Generates a random integer.
4. Date and Time Functions:
- date(): Formats a local time/date.
- time(): Returns the current Unix timestamp.
- strtotime(): Parses a time string into a Unix timestamp.
5. File System Functions:
- file_get_contents(): Reads entire file into a string.
- file_put_contents(): Write a string to a file.
- is_file(): Checks whether a file or directory exists.
6. Database Functions:
- mysqli_connect(): Opens a new connection to the MySQL server.
- mysqli_query(): Performs a query on the database.
- mysqli_fetch_assoc(): Fetches a result row as an associative array.
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