Data commit

Task/Apply-a-callback-to-an-array/Perl/apply-a-callback-to-an-array.pl

@@ -0,0 +1,30 @@
+# create array
+my @a = (1, 2, 3, 4, 5);
+
+# create callback function
+sub mycallback {
+  return 2 * shift;
+}
+
+# use array indexing
+for (my $i = 0; $i < scalar @a; $i++) {
+  print "mycallback($a[$i]) = ", mycallback($a[$i]), "\n";
+}
+
+# using foreach
+foreach my $x (@a) {
+  print "mycallback($x) = ", mycallback($x), "\n";
+}
+
+# using map (useful for transforming an array)
+my @b = map mycallback($_), @a;                # @b is now (2, 4, 6, 8, 10)
+
+# and the same using an anonymous function
+my @c = map { $_ * 2 } @a;                     # @c is now (2, 4, 6, 8, 10)
+
+# use a callback stored in a variable
+my $func = \&mycallback;
+my @d = map $func->($_), @a;                  # @d is now (2, 4, 6, 8, 10)
+
+# filter an array
+my @e = grep { $_ % 2 == 0 } @a;               # @e is now (2, 4)