The difference between == and === in php

The difference between == and === in PHP

== and === in PHP are both equality comparisons operators, but they differ in how they compare.

==

• Loose comparison: compares the contents of two values, but allows type conversion.
• For example: '10' == 10 is true because the string "10" will be automatically converted to an integer.

===

• Strict comparison: compares the content and type of two values, no type conversion is allowed.
• For example: '10' === 10 is false because the string "10" and the integer 10 have different types.

When to use ==

• When you don't care about the type of the operands.
• For example, when comparing the contents of two variables for equality.

When to use ===

• When you need to ensure that the types of the operands are exactly equal.
• For example, when comparing whether a variable is an object of a specific type.

Example

The following example demonstrates the difference between == and ===:

$a = 1;
$b = '1';

var_dump($a == $b); // 输出：true (松散比较)
var_dump($a === $b); // 输出：false (严格比较)

In the above example, $ a and $b have the same content, but different types. Therefore, a loose comparison (==) returns true, while a strict comparison (===) returns false.

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