There are four types of equivalence operations in the PHP language:
- Equivalence Operation (==): It evaluates to true if the two operands are equivalent, i.e., they can be converted to a common data type in which they have the same value but are not necessarily of the same type.
- Identity Operation (===): It evaluates to true only if the operands are of the same data type and have the same value.
- Not-equivalent Operation (!=): It evaluates to true if the two operands are not equivalent, without regards to their data type.
- Not-identical Operation (!==): It evaluates to true if the two operands are not of the same data type or do not have the same value.