Equality
Equality determines whether two expressions have equivalent values.
Related concepts: OperatorValue
Closest Wikipedia entry: Equality (mathematics) — In mathematics, equality is a relationship between two quantities or, more generally, two mathematical expressions, asserting that the quantities have the same value, or that the expressions represent the same mathematical object. Equality between A and B is written A = B, and pronounced "A equals B". In this equality, A and B are the members of the equality and are distinguished by calling them left-hand side or left member, and right-hand side or right member.
Misconceptions about Equality12 documented Misconceptions
Check YourselfAssignCompares — Java
= compares two valuesAssignCompares — Python
= compares two valuesCompareBooleanToConstant — Scratch
To test whether an expression evaluates to true or false, one must compare it to a constantComparisonWithBoolLiteral — Python
To test whether an expression is True or False, one must compare it to True or to FalseComparisonWithBooleanLiteral — Java
To test whether an expression is true or false, one must compare it to true or to falseEqualityOperatorComparesListIdentities — Scratch
(list a) = (list b) compares the identities of list a and list bEqualityOperatorComparesObjectsValues — Java
o==p compares the objects referred to by variables o and pEqualityOperatorComparesObjectsValues — JavaScript
The equality operator compares two objects' valuesEqualityOperatorComparesOnlyTypes — JavaScript
The equality operator '==' compares only the types of the operandsEqualityOperatorComparesOnlyTypes — Scratch
() = () compares only the types of its operandsEqualsComparesReferences — Java
o.equals(p) compares the references stored in the variables o and pNullAndUndefinedAreTheSame — JavaScript
The values null and undefined are the same