`map` method on arrays within an array

Question

I am using nested map on has_many association in following method

@trial.treatment_selections
.map { |ts| ts.establishment_methods.map { |em| em.final_establishment.to_f }}
# => [[10.2, 10.1, 10.1], [11.4, 11.4, 10.9]]

Here treatment_selections has_many establishment_methods.

I'm not sure how to get following array:

[10.2, 10.1, 10.1, 11.4, 11.4, 10.9]

Raj · Accepted Answer · 2018-11-27 02:40:05Z

2

Try flat_map:

<%= @trial.treatment_selections.flat_map { |ts| ts.establishment_methods.map { |em| em.final_establishment.to_f }} %>

answered Nov 27, 2018 at 2:40

Raj

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1 Comment

DollarChills Over a year ago

Spot on. Cheers @emaillenin.

Pramod Shinde · Accepted Answer · 2018-11-27 08:17:06Z

0

You can also use flatten method of an Array

@trial.treatment_selections
      .map { |ts| ts.establishment_methods.map { |em| em.final_establishment.to_f }}
      .flatten
#=> [10.2, 10.1, 10.1, 11.4, 11.4, 10.9]

edited Nov 27, 2018 at 8:17

answered Nov 27, 2018 at 8:09

Pramod Shinde

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