Functions and Arrays in PHP - Formula Sheet

Core Syntax and Formulas

Function Definition Structure

Defines a modular block of code with a unique identifier and optional parameters.

Syntax: function functionName(parameter1, parameter2) { code to execute; }

• function: The mandatory keyword used to initialize a custom function definition.
• functionName: The unique identifier for the function, which must start with a letter or underscore and is case-insensitive.
• parameter1, parameter2: Optional placeholder variables used to receive values during execution.

Function Calling Syntax

Executes a declared function by passing appropriate runtime values.

Syntax: functionName(argument1, argument2);

• argument1, argument2: The actual values or variables passed to the function during invocation.

Indexed Array Initialization

Creates a list of values indexed by sequential integers starting from 0.

Syntax 1: arrayVariable = [value1, value2, value3];

Syntax 2: arrayVariable = array(value1, value2, value3);

Associative Array Initialization

Creates a key-value store using explicit key associations.

Syntax: arrayVariable = array(key1 => value1, key2 => value2);

• key1, key2: Custom labels used as unique index identifiers.
• =>: The key association operator that maps an index key to its corresponding value.
• value1, value2: The data elements of any type stored stored under their respective keys.

Multidimensional Array Element Access

References nested elements inside a layered array structure.

Syntax: arrayVariable[outer_index][inner_index];

• outer_index: The index pointing to the outer array.
• inner_index: The nested index pointing to the specific item inside the inner array.