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Ruby collection method


each
a = [{b: 1}, {b: 2}, {b:3}]
a.each { |e| e[:b] }
=> [{:b=>1}, {:b=>2}, {:b=>3}]

find_all, select, filter
a = [{b: 1}, {b: 2}, {b:3}]
a.select { |e| e[:b] > 1 }
=> [{:b=>2}, {:b=>3}]

map, collect
a = [{b: 1}, {b: 2}, {b:3}]
a.map { |e| e[:b] }
=> [1, 2, 3]

filter_map
a = [{b: 1}, {b: 2}, {b:3}]
a.filter_map { |e| e if e[:b] > 1 }
=> [{:b=>2}, {:b=>3}]

reject
a = [{b: 1}, {b: 2}, {b:3}]
a.reject { |e| e[:b] > 1 }
=> [{:b=>1}]

inject
a = [1,2,3]
a.inject { |sum, e| sum + e }
=> 6

a = [{b: 1}, {b: 2}, {b:3}]
a.inject(0) {|sum,e| sum + e[:b] }
=> 6

a.inject([]) {|sum,e| sum << e[:b] }
=> [1, 2, 3]
#ruby-collection-method (1) #each (1) #for-loop (1) #ruby (16) #rails (40)
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