Dynamically Create String in Ruby

Question

There is a hash {'results' => [], 'snow' => [], 'ham' => [], 'plow' => [] }

and I want to build a string dynamically (the keys may change), which has all the keys, excluding "results", which looks like this "snow + ham + plow"

How do i do this?

yeah you're right, i was using python syntax, i'll edit the post and fix it — appleLover
– appleLover, Commented Mar 27, 2014 at 3:06

Paige Ruten · Accepted Answer · 2014-03-27 02:40:35Z

3

Use Hash#keys to get the keys, Array#reject to reject the "results" one, and Array#join to join them into a String:

hash.keys.reject { |k| k == "results" }.join(" + ")

answered Mar 27, 2014 at 2:40

Paige Ruten

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Cary Swoveland · Accepted Answer · 2014-03-27 05:20:01Z

3

Two other ways (#1 being my preference):

h = {'results' => [], 'snow' => [], 'ham' => [], 'plow' => [] }

#1

(h.keys - ['results']).join(' + ') #=> "snow + ham + plow"

#2

a = h.keys
a.delete('results')
a.join(' + ') #=> "snow + ham + plow"

edited Mar 27, 2014 at 5:20

answered Mar 27, 2014 at 3:06

Cary Swoveland

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2 Comments

Chuck Over a year ago

Well, without explicit enumeration. Array#delete and Array.join both have to iterate behind the scenes.

Cary Swoveland Over a year ago

Good point, @Chuck. No denying that. (Applies to keys as well.) Edited. Readers: formerly I said "Without iterating:".

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