CODEWITHSUNDEEP
perl
Trí Trương
Trí Trương

Reputation: 31

Output elements in array using perl

I have an array like this:

my @array = qw( zero one two three four five six seven eigth nine);

How to output a subarray consisting of strings of length 4 from @array. For example, if the string is equal to 4, the new array will be output as @subarray = ( zero four five nine )

Upvotes: 1

Views: 47

Answers (1)

Silvio Mayolo
Silvio Mayolo

Reputation: 70267

The built-in function grep serves as the "filter" operation in Perl, capable of filtering a list based on a regular expression or an arbitrary block.

If given a block, grep will call the block for each element of the list, setting the implicit variable $_ to the current value. It will keep the values which return truthy. So your filter would look like

my @subarray = grep { length == 4 } @array;

length, like a lot of built-in Perl functions, can take an argument (length($a), etc.), but when called without one it automatically takes the implicit variable $_ as an argument.

You can also pass it a regular expression. This is mainly useful if you're worried your coworkers like you too much and want to make some enemies.

my @subarray = grep(/^.{4}$/, @array);

Upvotes: 5

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