When and How to Use the Elvis Operator (?:) in PHP?

The Elvis Operator (?:) in PHP

In PHP, the ?: operator is known as the Elvis operator, a conditional expression that simplifies the common use case of assigning a default value to a variable if the original value is null or falsey.

Using the Elvis Operator

The Elvis operator evaluates to the left operand if the left operand is truthy (not null, not false, and not an empty string). Otherwise, it evaluates to the right operand.

Syntax

variable = expression_to_test ?: default_value;

Examples

• Assign 'foo' to the variable 'bar' if it's null or falsey:

  $bar = $foo ?: 'foo';

• In the example you provided:

  $items = $items ?: $this->_handle->result('next', $this->_result, $this);

  This assigns the result of $this->_handle->result('next', $this->_result, $this) to $items if $items is null or falsey.

Advantages of the Elvis Operator

• Code optimization: It eliminates the need for nested ternary operators or if-else statements.
• Improved readability: It makes code more concise and easier to understand.

Elvis Operator vs. Ternary Operator

While the Elvis operator and ternary operator (?: :) both evaluate expressions based on conditions, there are key differences:

• The Elvis operator only evaluates the left operand if the condition is true.
• The ternary operator evaluates both the true and false expressions regardless of the condition.

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