大家早上好。我是 Rails 的新手，我正在使用谷歌翻譯在這里發帖。
我有一個array, 我想從陣列中取出一定數量的值，并將它們放入一個新array1的 中，例如，前 7 個數字，然后是第二個陣列中的下 7 個數字：
array = [ 1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20, 21,22,23,24 ,25,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40]
array2 = []
array3 = []
array = [15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33,34,35,36,37,38 ,39,40]
array2 = [1,2,3,4,5,6,7]
array3 = [8,9,10,11,12,13,14]
我怎么能這樣做？
uj5u.com熱心網友回復：
您可以使用 Ruby shift Array 方法來完成此操作：
array = [1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40]
array2 = array.shift(7) # array2 is now [1, 2, 3, 4, 5, 6, 7]
array3 = array.shift(7) # array3 is now [8, 9, 10, 11, 12, 13, 14]
請注意，該shift方法也會編輯您的原始陣列。
順便說一句，這是純 Ruby（編程語言），這里沒有 Rails（框架）！希望這可以幫助。
uj5u.com熱心網友回復：
我想你需要each_slice這里：
res = array.each_slice(7).to_a
您將獲得每個子陣列長度為 7 的陣列。最后一個元素將剩余：
# outputs below
[
[1, 2, 3, 4, 5, 6, 7],
[8, 9, 10, 11, 12, 13, 14],
[15, 16, 17, 18, 19, 20, 21],
[22, 23, 24, 25, 26, 27, 28],
[29, 30, 31, 32, 33, 34, 35],
[36, 37, 38, 39, 40]
]
然后你可以使用each遍歷元素
res.each { |subarray| # do with subarray what you need }
或者您可以使用以下方法獲取所需的任何元素：
first_subarray = res.first
second_subarray = res.second
last_subarray = res.last
# or by index
third_subarray = res[2]
這里的關鍵是您的初始array值不會被反映
uj5u.com熱心網友回復：
這里有三種方法可以做到這一點。
使用陣列#slice！
array = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15,
16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28,
29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40]
array2 = array.slice!(0,7)
#=> [1, 2, 3, 4, 5, 6, 7]
array3 = array.slice!(0,7)
#=> [8, 9, 10, 11, 12, 13, 14]
現在，
array
#=> [15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27,
# 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40]
If arrayis not to be mutated 使用Array#slice并添加一個附加變數（例如，array1）。
array2 = array.slice(0..6)
#=> [1, 2, 3, 4, 5, 6, 7]
array3 = array.slice(7..13)
#=> [8, 9, 10, 11, 12, 13, 14]
array1 = array.slice(14..)
#=> [15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27,
# 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40]
使用Enumerable#slice_before
i = 0
array2, array3, array = array.slice_before { [8, 15].include?(i = 1) }.to_a
#=> [[1, 2, 3, 4, 5, 6, 7],
# [8, 9, 10, 11, 12, 13, 14],
# [15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27,
# 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40]]
現在，
array2
#=> [1, 2, 3, 4, 5, 6, 7]
array3
#=> [8, 9, 10, 11, 12, 13, 14]
array
#=> [15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27,
# 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40]
If arrayis not to be mutated在等號的左側array替換為。array1
磁區索引并使用Array#values_at
array2, array3, array = [[*0..6], [*7..13], [*14..(array.size-1)]].
map { |a| array.values_at(*a) }
#=> [[1, 2, 3, 4, 5, 6, 7],
# [8, 9, 10, 11, 12, 13, 14],
# [15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27,
# 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40]]
If arrayis not to be mutated在等號的左側array替換為。array1
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