FAQ 5.39 Why do I get weird spaces when I print an array of lines?

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5.39: Why do I get weird spaces when I print an array of lines?

(contributed by brian d foy)

If you are seeing spaces between the elements of your array when you
print the array, you are probably interpolating the array in double
quotes:

my @animals = qw(camel llama alpaca vicuna);
print "animals are: @animals\n";

It's the double quotes, not the "print", doing this. Whenever you
interpolate an array in a double quote contexts, Perl joins the elements
of spaces (or whatever is in $", which is a space by default):

animals are: camel llama alpaca vicuna

This is different than print the array without the interpolation:

my @animals = qw(camel llama alpaca vicuna);
print "animals are: ", @animals, "\n";

Now the output doesn't have the spaces between the elements because the
elements of @animals simply becoming part of the list to "print":

animals are: camelllamaalpacavicuna

You might notice this when each of the elements of @array end with a
newline. You expect to print one element per line, but notice that every
line after the first is indented:

this is a line
this is another line
this is the third line

That extra space comes from the interpolation of the array. If you don't
want to put anything between your array elements, don't use it in double
quotes. You can send

print @lines;

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