Ruby new unique array of nested array items

Question

Looking for a way to reduce a nested list of arrays, into a single array of items that are unique, and drop any empty arrays.

Looking to reduce this array:

[[2700, 177, 2092, 176, 188], [123, 1234], []]

Down to this new array:

[2700, 177, 2092, 176, 188, 123, 1234]

Have tried array.uniq.compact, but did not work.

Thanks for any suggestions.

Answer 1

You need to flatten the array first.

array.flatten.uniq

A few notes:

• Array#flatten merges all child arrays into the top level array. Since empty arrays do not contain any elements, they will automatically be removed.
• Array#compact returns a new array with the nil elements removed.
• Array#uniq returns a new array with only unique elements.