Perl: Index of array returned from method

Question

I have the following code:

#!/usr/bin/perl

use strict;
use feature qw(say);

my $raw_text = "a b c d e f g h";

my @array = split(/ /, $raw_text);
my $element = @array[0];

say "Element [0] of array is : ", $array[0];

This prints on STDOUT:

Element [0] of array is : a

So far, so good. However if I want to retrieve the element straightforward from the split method, I would think of:

my $element = split(/ /, $raw_text)[0];

But it turns out that this throws a compilation error. Doing some research I figured out that I have to type:

my $element = ( split(/ /, $raw_text) )[0];

The question is: Why are the extra parenthesis necessary?

I might be missunderstanding the parenthesis meaning for this case.

Borodin · Accepted Answer · 2018-04-19 11:06:29Z

3

The syntax error is to force you to disambiguate the expression, which could be interpreted as either

split((/ /, $raw_text)[0])

or

(split(/ /, $raw_text))[0]

In general, Perl will make a "best guess" at the intention of ambiguous code, but in this case the designers decided that there was no real way to decide on a "most likely" interpretation, and so caused the construct to fail in compilation to force the author to disambiguate the code

Note that the inner parentheses are superfluous, and the expression may be written like so

(split / /, $raw_text)[0]

edited Apr 19, 2018 at 11:06

answered Apr 19, 2018 at 10:31

Borodin

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1 Comment

ppinto Over a year ago

I would have never thought of writing the expression as (split / /, $raw_text)[0]. Certainly, it makes much more sense now. Thank you!

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