"Perl for Perl Newbies" - Part 1ArraysThe x operator

9.5. The x operator

The expression (@array) x $num_times returns an array that is composed of $num_times copies of @array one after the other. The expression $scalar x $num_times, on the other hand, returns a string containing $num_times copies of $scalar concatenated together string-wise.

Therefore it is important whether the left operand is wrapped in parenthesis or not. It is usually a good idea to assign the left part to a variable before using x so you'll have the final expression ready.

Here's an example to illustrate the use:

print "Test 1:\n";
@myarray = ("Hello", "World");
@array2 = ((@myarray) x 5);
print join(", ", @array2), "\n\n";

print "Test 2:\n";
@array3 = (@myarray x 5);
print join(", ", @array3), "\n\n";

print "Test 3:\n";
$string = "oncatc";
print (($string x 6), "\n\n");

print "Test 4:\n";
print join("\n", (("hello") x 5)), "\n\n";

print "Test 5:\n";
print join("\n", ("hello" x 5)), "\n\n";

Can you guess what the output of this program will be?

Here's a spoiler

Test 1:
Hello, World, Hello, World, Hello, World, Hello, World, Hello, World

Test 2:
22222

Test 3:
oncatconcatconcatconcatconcatconcatc

Test 4:
hello
hello
hello
hello
hello

Test 5:
hellohellohellohellohello

Written by Shlomi Fish