close
a = [1,2,3,4]
b = a.map {|x| x*x } #b=[1, 4, 9, 16]
c = a.select {|x| x%2==0 } #c=[2,4]
d=a.inject(0){|sum,x| sum+=x**2} #d=30
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反正就是一整個好玩!!!(  ̄ c ̄)y▂ξ
a = [1,2,3,4]
b = a.map {|x| x*x } #b=[1, 4, 9, 16]
c = a.select {|x| x%2==0 } #c=[2,4]
d=a.inject(0){|sum,x| sum+=x**2} #d=30