when - Perldoc Browser

#when EXPR BLOCK

#when BLOCK

when is analogous to the case keyword in other languages. Used with a foreach loop or the experimental given block, when can be used in Perl to implement switch/case like statements. Available as a statement after Perl 5.10 and as a statement modifier after 5.14. Here are three examples:

 use v5.10;
 foreach (@fruits) {
 when (/apples?/) {
 say "I like apples."
 }
 when (/oranges?/) {
 say "I don't like oranges."
 }
 default {
 say "I don't like anything"
 }
 }
 # require 5.14 for when as statement modifier
 use v5.14;
 foreach (@fruits) {
	say "I like apples." 	 when /apples?/; 
	say "I don't like oranges." when /oranges?;
 default { say "I don't like anything" }
 }
 use v5.10;
 given ($fruit) {
 when (/apples?/) {
 say "I like apples."
 }
 when (/oranges?/) {
 say "I don't like oranges."
 }
 default {
 say "I don't like anything"
 }
 }

See "Switch statements" in perlsyn for detailed information.

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