How Does the Spaceship Operator () Work in PHP 7?

The Spaceship Operator (<=>) in PHP 7

Introduction

PHP 7 introduced the Spaceship operator, also known as the "Spaceship" operator. This operator simplifies the process of combined comparison, returning different values based on the relationship between the operands.

How Does the Spaceship Operator Work?

The <=> operator works by comparing the operands and returning:

• 0 if the values are equal
• 1 if the left operand is greater
• -1 if the right operand is greater

Comparison Rules

The Spaceship operator follows the same comparison rules as other comparison operators in PHP, such as <, <=, ==, >=, and >. This means that:

• Numbers are compared numerically.
• Strings are compared lexicographically (ASCII values of characters).
• When comparing different data types, PHP converts the operands to a common type.

Use Cases

The Spaceship operator is particularly useful in situations where you need to compare multiple values with a single operator. For example:

• Sorting arrays or collections
• Performing range checks
• Determining the direction of movement (e.g., in pagination)

Example

Consider the following code:

<code class="php">echo 1 <=> 1; // Output: 0
echo 3 <=> 4; // Output: -1
echo "x" <=> "x"; // Output: 0
echo "x" <=> "y"; // Output: -1</code>

In this example:

• When comparing integers, the operator returns 0 if they are equal, -1 if the left operand is smaller, and 1 if the right operand is smaller.
• When comparing strings, the operator compares the characters lexicographically, returning 0 if they are equal, -1 if the left character is smaller, and 1 if the right character is smaller.

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