Functions In PHP
Functions In PHP
A function is an independent block of code that takes input in the form of parameters and returns a result to the caller. In other words, a function can also be described as a block of code that performs a specific function. Functions in PHP are no different than function in any other programming language.
- A block of code for specific tasks.
- Save compile-time –only compile once.
- Reuse many times when needed.
- Optimize your code.
Built-in functions like print(); date();
- User-defined functions:
- Function names cannot have spaces.
- The function name must begin with a letter or underscore.
E.g., call a built-in function abs();
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<?php $num=-5; $new_num=abs($num); echo $new_num; ?> |
How to Declare a Function in PHP
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function function_name(arguments) { block of codes and statements; } |
- You can declare a function below a call to it.
- May have none, one, or multiple arguments each separated by a comma.
- Write function name followed by ( ), even if the function doesn’t have any arguments.
Example-
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<?php function print_br($str) { print "$str <br>"; } print_br("line1"); print_br("line2"); ?> |
Functions – Return Value
- Functions may have a return value.
- The return value in a function returns the value to the function that may be used later on while calling a function.
- You may need to access the value that the function returns, but you may not need to print it out, that’s why you use a return value for a function.
Example-Functions – Return Value
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<?php function multiply_by_two($value){ $result=$value*2; return $result; } echo multiply_by_two(7); ?> |
Example-Functions – Without Return Value
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<?php function multiply_by_two($value){ $result=$value*2; echo $result; } multiply_by_two(7); ?> |
PHP built-in Functions
Sqrt(); — Take the square root of a number
Ceil(); — Take ceil of a decimal number
Floor(); — take the floor of a decimal number
Max(); — take the max number
Min(); — take the min number
Strtolower(); — convert string to lower case
Strtoupper(); — convert string to upper case