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Enumerable#inject のブロック内の制御にちょっと注意！

Last updated at 2013-11-15Posted at 2013-11-15

injectで割と以下の失敗をよくします。。。

誤

pry

2.0.0 (main)> (0..2).inject([]) {|ary, i| next if i == 1; ary << i}

NoMethodError: undefined method `<<' for nil:NilClass
from (pry):2:in `block in __pry__'

pry

2.0.0 (main)> (0..2).inject([]) {|ary, i| next ary if i == 1; ary << i}

=> [
    [0] 0,
    [1] 2
]