Educator

Arrays

• An array is a composite data type meaning it can hold more than one piece of data simultaneously, unlike scalar data types.
• Arrays in PHP are treated as maps where values are associated, or mapped, to keys .
• Keys can only be either integers or strings. However, values can be any PHP data type, including other arrays.
• Array values can be repeated, but keys must be unique.
• Arrays with integers as keys are known as numerically-indexed, or simply, indexed arrays .
• Arrays with strings as keys are known as associative arrays .
• Arrays are typically declared using the array() construct.
• Associative arrays use the => operator to assign keys with values.
• Data in arrays is accessed using square bracket syntax .
• For indexed arrays, the integer key of the desired value is listed between the brackets. Indexed array keys always start with the index 0.
• For associative arrays, the string key of the desired value is listed in quotes between the brackets.
• print_r() is a function used to output the value of variables in a formatted fashion.
• Additional Resources:
  • PHP Manual - Arrays
  • Function Reference - print_r()