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Perl Language Reference Manual
by Larry Wall and others
Paperback (6"x9"), 724 pages
ISBN 9781906966027
RRP £29.95 ($39.95)

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scalar EXPR

Forces EXPR to be interpreted in scalar context and returns the value of EXPR.

@counts = ( scalar @a, scalar @b, scalar @c );

There is no equivalent operator to force an expression to be interpolated in list context because in practice, this is never needed. If you really wanted to do so, however, you could use the construction @{[ (some expression) ]}, but usually a simple (some expression) suffices.

Because scalar is a unary operator, if you accidentally use for EXPR a parenthesized list, this behaves as a scalar comma expression, evaluating all but the last element in void context and returning the final element evaluated in scalar context. This is seldom what you want.

The following single statement:

print uc(scalar(&foo,$bar)),$baz;

is the moral equivalent of these two:


See 7 for more details on unary operators and the comma operator.

ISBN 9781906966027Perl Language Reference ManualSee the print edition