Ruby 配列を条件により満たすものと満たさないものに分割する

# 元の配列は影響を受けません
[配列].partition {|x| ...}

arr = [1, 2, 3, 4, 5, 6, 7]

arr1, arr2 = arr.partition {|x| x >= 3} 

p arr1
# [3, 4, 5, 6, 7]

p arr2
# [1, 2]

p arr
# [1, 2, 3, 4, 5, 6, 7]

arr = [1, 2, 3, 4, 5, 6, 7]


arr1, arr2 = arr.partition {|x| x % 2 == 1 } 

p arr1
# [1, 3, 5, 7]

p arr2
# [2, 4, 6]

p arr
# [1, 2, 3, 4, 5, 6, 7]