CODEWITHSUNDEEP
phpdatetimeobjectcomparison-operators
LBA
LBA

Reputation: 4089

Strict comparison of DateTime Objects

I am doing a strict comparison on a list of objects, just to identify objects which might have changed, like:

if ($oldValue !== $newValue)

in some cases $oldValue and $newValue are DateTime objects.

Debugging my app I am getting the following output for my two values just before comparing them:

DateTime Object ( [date] => 2017-04-24 00:00:00.000000 [timezone_type] => 3 [timezone] => UTC )

DateTime Object ( [date] => 2017-04-24 00:00:00.000000 [timezone_type] => 3 [timezone] => UTC )

Why is my comparison/condition still true?

Upvotes: 8

Views: 1560

Answers (1)

John Conde
John Conde

Reputation: 219814

When comparing objects in PHP, the === operator does not compare values. It compares instances. This means unless both objects point to the same object, they are not strictly equal.

When using the comparison operator (==), object variables are compared in a simple manner, namely: Two object instances are equal if they have the same attributes and values (values are compared with ==), and are instances of the same class.

When using the identity operator (===), object variables are identical if and only if they refer to the same instance of the same class.

Upvotes: 11

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