Insert intermediate elements into array

Question

What is the best way in which to insert an element between each existing element of an array. The best I have so far is as follows:

my @array = ( 1 , 'foo', { }, [ ] );
my @new_array;
push @new_array, $_, ', ' for @array;
pop @new_array;

In reality, @array contains a mixture of HTML::Element objects and strings that are passed to HTML::Element's splice_content method with the aim of comma separating part of an elements contents.

That's not a bad way. I was thinking List::MoreUtils::zip would help, but you still have to create the array of (', ') x $#array to be the alternate items, so it doesn't look like a big saving over this. — Jim Davis
– Jim Davis, Commented Jul 12, 2015 at 0:41
Thank you for the zip suggestion, checking for a solution via the List::* modules hadn't crossed my mind. — Chris
– Chris, Commented Jul 12, 2015 at 1:10

cjm · Accepted Answer · 2015-07-12 00:56:02Z

3

How about:

my @array = ( 1 , 'foo', { }, [ ] );
(undef, my @new_array) = map {; ', ' => $_ } @array;

This takes advantage of the little known fact that you can use undef on the left-hand side of a list assignment to indicate that you don't care about that element. (The semicolon in map {; is to make the parser understand that's a block and not a hashref.)

answered Jul 12, 2015 at 0:56

cjm

62.2k9 gold badges133 silver badges179 bronze badges

Sign up to request clarification or add additional context in comments.

1 Comment

Chris Over a year ago

Very nice alternative. I was puzzling over the resultant syntax error before your semicolon fix.

Borodin · Accepted Answer · 2015-07-12 04:44:03Z

3

I think I would use a map instead of a for loop but keep your pop

my @new_array = map { $_, ', ' } @array;
pop @new_array;

answered Jul 12, 2015 at 4:44

Borodin

127k9 gold badges72 silver badges146 bronze badges

1 Comment

Chris Over a year ago

In the back of my mind, I wanted rid of that lonesome pop, but this solution certainly keeps the intentions clear.

Collectives™ on Stack Overflow

Insert intermediate elements into array

2 Answers 2

1 Comment

1 Comment

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

1 Comment

1 Comment

Your Answer

Sign up or log in

Post as a guest

Related