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 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:
&foo; print(uc($bar),$baz);
See perlop for more details on unary operators and the comma operator.