Which operator is used for checking type and value equality in PHP?

The operator used for checking both type and value equality in PHP is the triple equal sign, represented as ===. This operator ensures that not only are the values being compared equal, but it also confirms that they are of the same type. For example, using === to compare an integer with a string that contains the same number will return false because, despite having the same numerical value, they are different types (integer vs. string).

This strict comparison is helpful in scenarios where type integrity is crucial, such as when dealing with data from various sources or in function parameter checks. The clarity it provides by enforcing both type and value checks helps prevent subtle bugs that can arise from implicit type juggling in PHP.

In contrast, other options involve different comparisons. For instance, != and !== are used for value comparison without strict type checking and can lead to type coercion. The use of + does not relate to comparison at all, as it is the addition operator in PHP. Therefore, the triple equal sign is the most precise for ensuring both data type fidelity and value equality in PHP applications.