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Introduction to Perl 6: arrays

In this screencast I provide a basic introduction to arrays in Perl 6.

• arrays
• <
• {
• qw
• for
• ->

Instead of using the REPL, in what you would now type EVAL instead of eval, here I am showing you the examples running from the command line.

Create an array, print the values:

examples/arrays/01.p6

use v6;

my @names = ("Foo", "Bar", "Moo");

say @names;

$ perl6 01.p6

Foo Bar Moo

Print the values in a way more useful for debugging:

examples/arrays/01_perl.p6

use v6;

my @names = ("Foo", "Bar", "Moo");

say @names.perl;

$ perl6 01_perl.p6

Array.new("Foo", "Bar", "Moo")

Element of an array:

examples/arrays/01_element.p6

use v6;

my @names = ("Foo", "Bar", "Moo");

say @names[1];

$ perl6 01_element.p6

Bar

Perl 5 users should note, the sigil has not changed! In Perl 6 there is sigil-invariance.

examples/arrays/01_all_elements.p6

use v6;

my @names = "Foo", "Bar", "Moo";

say @names[];

$ perl6 01_all_elements.p6

Foo Bar Moo

No need for parentheses around the elements of a list in assignment:

examples/arrays/01_no_parens.p6

use v6;

my @names = "Foo", "Bar", "Moo";

say @names[];

$ perl6 01_no_parens.p6

Foo Bar Moo

Interpolation

Normally arrays don't interpolate in a string:

examples/arrays/02_interpolate.p6

use v6;

my @names = "Foo", "Bar", "Moo";

say "Hello @names how are you?";

$ perl6 02_interpolate.p6

Hello @names how are you?

However, if we put quare brackets after the arrat then we can achive interpolation:

examples/arrays/02_interpolate_with_square.p6

use v6;

my @names = "Foo", "Bar", "Moo";

say "Hello @names[] how are you?";

$ perl6 02_interpolate_with_square.p6

Hello Foo Bar Moo how are you?

We can interpolate a single element of the array:

examples/arrays/02_interpolate_element.p6

use v6;

my @names = "Foo", "Bar", "Moo";

say "Hello @names[1] how are you?";

$ perl6 02_interpolate_element.p6

Hello Bar how are you?

A more generic way would be to put the expression in curly braces:

examples/arrays/02_interpolate_with_curly.p6

use v6;

my @names = "Foo", "Bar", "Moo";

say "Hello {@names} how are you?";

$ perl6 02_interpolate_with_curly.p6

Hello Foo Bar Moo how are you?

Interpolate expression

Inside the curly braces we can put any expression. Perl 6 will evaluate the expression and the result will be interpolated in the string.

examples/arrays/03.p6

use v6;

my @names = "Foo", "Bar", "Moo";

say "Hello { join('; ', @names) } how are you?";

$ perl6 03.p6

Hello Foo; Bar; Moo how are you?

Pointy brackets

Using pointy brackets to create an array is like qw in Perl 5. examples/arrays/04.p6

use v6;

my @names = <Foo Bar Moo>;

say "Hello {@names} how are you?";

$ perl6 04.p6

Hello Foo Bar Moo how are you?

for-loop

Iterating over the elements of an array using the for loop:

examples/arrays/05.p6

use v6;

my @names = <Foo Bar Moo>;

for @names -> $n {
    say $n;
}

$ perl6 05.p6

Foo
Bar
Moo

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Written by Gabor Szabo

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Published on 2015-02-02

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