convert hashed array to string

Question

hash = { "d" => [11, 22], "f" => [33, 44, 55] }

is there an one liner to get a string like below:

d:11,d:22,f:33,f:44,f:55

thanks!

Great, thanks for the tip. Why this code doesn't work, only difference is I replaced vs.map with vs.each:

hash.map {|k,vs| vs.each {|v| "#{k}:#{v}"}}.join(",")

which returns "11,22,33,44,55"

sepp2k · Accepted Answer · 2011-03-09 23:25:05Z

3

Use two nested calls to map to get an array of arrays of "key:value" strings, and then use join to turn it into one comma-separated string:

hash.map {|k,vs| vs.map {|v| "#{k}:#{v}"}}.join(",")

answered Mar 9, 2011 at 23:25

sepp2k

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2 Comments

user612308 Over a year ago

why this code doesn't work, only difference is i replaced "vs.map" with "vs.each", hash.map {|k,vs| vs.each {|v| "#{k}:#{v}"}}.join(","), which returns "11,22,33,44,55"

sepp2k Over a year ago

@user: Because each executes the block on each element, but throws the results away and then returns the receiver unchanged. You use each for the side-effects of the block only and in this case there are none. So in other words your code does the same as just hash.map {|k,vs| vs}.join(",").

hoha · Accepted Answer · 2011-03-09 23:26:13Z

0

hash.keys.map {|k| hash[k].map {|v| "#{k}:#{v}"}}.flatten.join(",")

answered Mar 9, 2011 at 23:26

hoha

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1 Comment

sepp2k Over a year ago

Actually you don't need to call flatten before calling join. Join flattens automatically.

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