Combining string elements from two separate arrays

Question

I have two arrays

names = ["name1", "name2"]
tracks = ["track1", "track2"]

I'm trying to combine the two arrays into one new array

data => ["name1 track1", "name2 track2"]

I tried the following

1)   @data = @name.zip(@tracks)flatten 
     produces ["name1", "track1", "name2", "track2"]

2)   @data = @name.at(0).concat(@tracks.at(0)) + @name.at(1).concat(@tracks.at(1))
     produces ["name1track1name2track2"]

3)   @name.each do |n|
      @tracks.each do |t|
       @data.push n + " " + t
       end
     end
     produces ["name1 track1", "name1 track2", "name2 track1", "name2 track2"]

I cannot seem to solve this problem. I would appreciate some help.

Those new to SO commonly select an answer too soon (and thereby discourage other answers) or never select an answer. If at least one answer meets your needs--as here (considering your comment on @steenslag's answer)--you should select the one you like best. There's no rush, just don't forget to do it. Have a look at this FAQ. — Cary Swoveland
– Cary Swoveland, Commented Feb 20, 2014 at 19:00

steenslag · Accepted Answer · 2014-02-20 15:42:29Z

6

names  = ["name1", "name2"] #note the "="
tracks = ["track1", "track2"]

p names.zip(tracks).map{|e| e.join(" ")}
#=> ["name1 track1", "name2 track2"]

answered Feb 20, 2014 at 15:42

steenslag

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1 Comment

user3333211 Over a year ago

I went with this answer and it has worked perfectly. Thank you so much!

dcarneiro · Accepted Answer · 2014-02-20 15:40:16Z

1

names.map {|name| "#{name} #{tracks[names.index(name)]}"}
=> ["name1 track1", "name2 track2"]

answered Feb 20, 2014 at 15:40

dcarneiro

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1 Comment

Cary Swoveland Over a year ago

If names => ['cat', 'cat'] there's a problem.

Agis · Accepted Answer · 2014-02-20 19:21:48Z

1

You can do it like this:

data = []
names.each_with_index {|x,y| data << "#{x} #{tracks[y]}" }
data # => ["name1 track1", "name2 track2"]

edited Feb 20, 2014 at 19:21

answered Feb 20, 2014 at 15:37

Agis

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Comments

DiegoSalazar · Accepted Answer · 2014-02-20 15:45:09Z

0

Here's a neat way to do it:

names = ["name1", "name2"]
tracks = ["track1", "track2"]

names.zip(tracks).map { |a| a.join(" ") }
# => ["name1 track1", "name2 track2"]

First,

names.zip(tracks)

gives us

[["name1", "track1"], ["name2", "track2"]]

And then we join the inner arrays with a space using map

answered Feb 20, 2014 at 15:45

DiegoSalazar

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Comments

xlembouras · Accepted Answer · 2014-02-20 16:00:54Z

0

I like the product method

=> array_size = names.size
=> names.product(tracks).
     each_with_index.
     map { |x,i| x.join(" ") if (i % array_size - i / array_size).zero? }.compact
=> ["name1 track1", "name2 track2"]

answered Feb 20, 2014 at 16:00

xlembouras

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2 Comments

Cary Swoveland Over a year ago

If array.size => 1,000, you'd create an array with one million elements, then throw away 999,000 of them!

xlembouras Over a year ago

yeap, didn't say it was, fast or cheap. :-)

Cary Swoveland · Accepted Answer · 2014-02-20 17:27:11Z

0

Another:

names.map { |s| s << ' ' << tracks.shift }
  #=> ["name1 track1", "name2 track2"]

If names (and/or tracks) cannot be modified, this would have to operate on a copy.

A variant:

[].tap { |a| names.size.times {a << (names.shift + ' ' + tracks.shift) } }

edited Feb 20, 2014 at 17:27

answered Feb 20, 2014 at 16:46

Cary Swoveland

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Comments

Arup Rakshit · Accepted Answer · 2014-02-20 17:30:15Z

0

A bit different way :

names  = ["name1", "name2"] 
tracks = ["track1", "track2"]

names.each_index.map { |i| "#{names[i]} #{tracks[i]}" }
# => ["name1 track1", "name2 track2"]

answered Feb 20, 2014 at 17:30

Arup Rakshit

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Comments

Abdo · Accepted Answer · 2014-02-20 19:56:44Z

0

Another way, very similar to @steenslag's (I sometimes hate opening blocks :-) )

names = ["name1", "name2", "name3"]
tracks = ["track1", "track2", "track3"]

names.zip([' '] * names.length, tracks).map(&:join)
=> ["name1 track1", "name2 track2", "name3 track3"]

answered Feb 20, 2014 at 19:56

Abdo

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