如何向新数组中输入数据
如何向新数组中输入数据
提问于 2022-06-13 11:23:24
大家早上好。我是Rails的新手，我用谷歌翻译在这里发布。
我有一个array，我想从数组中获取一定数量的值，并将它们放入一个新的array1中，例如，前7个数字，然后第二个数组中的接下来的7个数字：
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]我怎么能这么做？
回答 3
Stack Overflow用户
回答已采纳
发布于 2022-06-13 17:29:58
有三种方法可以做到这一点。
使用 Array#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]现在,
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]如果array不发生变异，请使用Array#slice并添加一个附加变量(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]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]]现在,
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]如果array不发生变异，请将array替换为等号左边的array1。
分区索引及使用 Array#values
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]]如果array不发生变异，请将array替换为等号左边的array1。
Stack Overflow用户
发布于 2022-06-13 11:31:40
您可以使用Ruby方法来完成这一任务：
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] 注意，shift方法也编辑了原始数组。
顺便说一下，这是纯Ruby (编程语言)，这里没有Rails (框架)！希望这能有所帮助。
Stack Overflow用户
发布于 2022-06-13 11:32:25
我想你需要each_slice：
res = array.each_slice(7).to_a你会得到每个子数组长度为7的数组。最后一个元素将保留如下：
# 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]
]然后您可以使用each来遍历元素
res.each { |subarray| # do with subarray what you need } 也可以使用以下方法获得任何您想要的元素：
first_subarray = res.first
second_subarray = res.second
last_subarray = res.last
# or by index
third_subarray = res[2]关键是你的初始array不会被反射
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原文链接：
https://stackoverflow.com/questions/72602010
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