Converting an array into string

Question

I need to join output of a hash into a string.

The hash looks like this:

 nas.location.walledgardens.to_s

  => "[#<Walledgarden id: 1, location_id: 12, url: \"polka.com\", created_at: \"2012-05-14 17:02:47\", updated_at: \"2012-05-14 17:02:47\">, #<Walledgarden id: 2, location_id: 12, url: \"test.com\", created_at: \"2012-05-14 17:02:47\", updated_at: \"2012-05-14 17:02:47\">, #<Walledgarden id: 3, location_id: 12, url: \"help.com\", created_at: \"2012-05-14 17:02:47\", updated_at: \"2012-05-14 17:02:47\">, #<Walledgarden id: 4, location_id: 12, url: \"yell.com\", created_at: \"2012-05-14 17:02:47\", updated_at: \"2012-05-14 17:02:47\">, #<Walledgarden id: 5, location_id: 12, url: \"sausage.com\", created_at: \"2012-05-14 17:02:47\", updated_at: \"2012-05-14 17:02:47\">]"

I need to join the url values into the following format:

polka.com,test.com,help.com

What the best way to do this? I can easily look through it but the output has line breaks and I need these removed plus the commas.

require 'csv'; nas.location.walledgardens.map(&:url).to_csv ? — Seamus Abshere
– Seamus Abshere, Commented May 14, 2012 at 20:24
@SeamusAbshere IMO, loading a CSV library is overkill for this simple example. But perhaps the OP is looking to apply this in a situation where the string needs to be parsed again later — in which case that's definitely a good idea. — jtbandes
– jtbandes, Commented May 14, 2012 at 20:31

MrDanA · Accepted Answer · 2012-05-14 20:25:12Z

6

nas.location.walledgardens.collect { |w| w.url }.join(",")

The .collect method will collect all what that block returns and put it in an array, and then the join puts that array in a string, separated by whatever you give it (so a comma).

answered May 14, 2012 at 20:25

MrDanA

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3 Comments

MrDanA Over a year ago

Actually Hauleth's map is better!

Michael Kohl Over a year ago

@MrDanA: Well map is just an alias for collect and &:url is just the Symbol#to_proc shortcut for your block, so in essence it's the same solution. :-)

MrDanA Over a year ago

@MichaelKohl I had no idea it was just a short cut like that, but it mainly just looks so much nicer. Thanks for the info though!

jtbandes · Accepted Answer · 2012-05-14 20:25:23Z

6

What you have is not a Hash, but an Array of Walledgarden objects (they look to be ActiveRecord::Base subclasses).

Try this:

nas.location.walledgardens.collect(&:url).join ","

(Note: #map and #collect are equivalent, so which one you choose should be a consideration of readability!)

answered May 14, 2012 at 20:25

jtbandes

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1 Comment

simonmorley Over a year ago

@phrogz! Yeah, you lot were too quick :) Thanks again

Phrogz · Accepted Answer · 2012-05-14 20:36:33Z

4

Use Array#map:

nas.location.walledgardens.map(&:url).join ','

edited May 14, 2012 at 20:36

Phrogz

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answered May 14, 2012 at 20:24

Hauleth

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