ЭЛЕКТРОННАЯ БИБЛИОТЕКА КОАПП |
Сборники Художественной, Технической, Справочной, Английской, Нормативной, Исторической, и др. литературы. |
4.5. Iterating Over an Array by ReferenceProblemYou have a reference to an array, and you want to use SolutionUse # iterate over elements of array in $ARRAYREF foreach $item (@$ARRAYREF) { # do something with $item } for ($i = 0; $i <= $#$ARRAYREF; $i++) { # do something with $ARRAYREF->[$i] } DiscussionThe solutions assume you have a scalar variable containing the array reference. This lets you do things like this: @fruits = ( "Apple", "Blackberry" ); $fruit_ref = \@fruits; foreach $fruit (@$fruit_ref) { print "$fruit tastes good in a pie.\n"; } We could have rewritten the for ($i=0; $i <= $#$fruit_ref; $i++) { print "$fruit_ref->[$i] tastes good in a pie.\n"; } Frequently, though, the array reference is the result of a more complex expression. You need to use the $namelist{felines} = \@rogue_cats; foreach $cat ( @{ $namelist{felines} } ) { print "$cat purrs hypnotically..\n"; } print "--More--\nYou are controlled.\n"; Again, we can replace the for ($i=0; $i <= $#{ $namelist{felines} }; $i++) { print "$namelist{felines}[$i] purrs hypnotically.\n"; } See Alsoperlref (1) and perllol (1); Chapter 4 of Programming Perl; Recipe 11.1; Recipe 4.4 |