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 expressions, stating that they have the same value, or 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 distinguished by calling them left-hand side (LHS), and right-hand side (RHS).

Misconceptions about Equality

12 documented Misconceptions

AssignCompares — Java

= compares two values

AssignCompares — Python

= compares two values

CompareBooleanToConstant — Scratch

To test whether an expression evaluates to true or false, one must compare it to a constant

ComparisonWithBoolLiteral — Python

To test whether an expression is True or False, one must compare it to True or to False

ComparisonWithBooleanLiteral — Java

To test whether an expression is true or false, one must compare it to true or to false

EqualityOperatorComparesListIdentities — Scratch

(list a) = (list b) compares the identities of list a and list b

EqualityOperatorComparesObjectsValues — Java

o==p compares the objects referred to by variables o and p

EqualityOperatorComparesObjectsValues — JavaScript

The equality operator compares two objects' values

EqualityOperatorComparesOnlyTypes — JavaScript

The equality operator '==' compares only the types of the operands

EqualityOperatorComparesOnlyTypes — Scratch

() = () compares only the types of its operands

EqualsComparesReferences — Java

o.equals(p) compares the references stored in the variables o and p

NullAndUndefinedAreTheSame — JavaScript

The values null and undefined are the same