In Variables§
See primary documentation in context for The $ variable
$_
is the topic variable. A fresh one is created in every block. It's also the default parameter for blocks that do not have an explicit signature, so constructs like for @array { ... }
and given $var { ... }
bind the value or values of the variable to $_
by invoking the block.
for <a b c> # binds $_ to 'a', 'b' and 'c' in turnsay for <a b c>; # same, even though it's not a blockgiven 'a' # binds $_ to 'a'say given 'a'; # same, even though it's not a block
Because $_
is bound to the value of the iteration, you can also assign to $_
if it is bound to something assignable.
my = ^5; # 0 through 4++ for ; # increment all elements of @numberssay ;# OUTPUT: «1 2 3 4 5»
CATCH
blocks bind $_
to the exception that was caught. The ~~
smartmatch operator binds $_
on the right-hand side expression to the value of the left-hand side.
Calling a method on $_
can be shortened by leaving off the variable name:
.say; # same as $_.say
m/regex/
and /regex/
regex matches and s/regex/subst/
substitutions work on $_
:
say "Looking for strings with non-alphabetic characters...";for <ab:c d$e fgh ij*># OUTPUT: «Looking for strings with non-alphabetic characters...# ab:c# d$e# ij*»