What do the square brackets in php mean?

Brackets ([]) are used in PHP for: 1. Array declaration and access; 2. Surrounding conditional statement code blocks; 3. Surrounding function definition code blocks; 4. Enclosing class definition code blocks.

The meaning of square brackets in PHP

The square brackets ([]) have two main meanings in PHP Purpose:

Array declaration

Brackets are used to declare and initialize arrays. An array is an ordered collection of key-value pairs. Each key-value pair is stored in an element surrounded by square brackets. For example:

<code class="php">$array = ['apple', 'banana', 'cherry'];</code>

Array access

Brackets are also used to access elements in an array. To access an element at a specific index, use square brackets and specify the index value. For example:

<code class="php">echo $array[1]; // 输出 "banana"</code>

Additionally, brackets have the following uses in PHP:

Conditional statements

Brackets are used to surround conditional statements (e.g. if, else, and switch).

Function definition

Brackets are used to surround code blocks in function definitions.

Class definition

Brackets are used to surround code blocks in class definitions.

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