elsepart

Elsepart refers to the portion of a conditional construct that executes when the condition being tested is false. It is commonly called the else clause or else branch and provides the alternative path when the then-part does not apply.

In many imperative languages, such as C, C++, Java, and JavaScript, the typical form is if (condition) { /* then-part */ } else { /* else-part */ }. In Python, the equivalent structure is if condition: ... else: .... Languages that use switch or match statements provide a default arm or case to handle inputs that do not match any explicit branch, serving a similar role to the else part.

The else part is optional in most languages; if the condition is false and no else part exists, no alternate action is taken. When present, exactly one path of the conditional will execute for a given evaluation. Some languages also support chained else-if (elif) branches to handle multiple conditions in sequence before reaching the final else part.

A common programming concern related to the else part is readability, especially with nested conditionals. The dangling-else problem arises when an else could pair with more than one if; languages resolve this by associating an else with the innermost unmatched if.

In expression-oriented languages, the conditional may yield a value, and the else part contributes the alternative value to the overall expression.

See also: if statement, conditional expressions, switch statement, default case.