重复向量直到第 n 个元素

Question

我要重复的向量是：

> months2014
[1] "07" "08" "09" "10" "11" "12"

我想根据这个定义第 n 个值的向量重复它：

> num_times
  [1]  6  6  6  6  5  6  6  5  6  6  6  6  6  6  6  6  6  6  6  6  6  6  6  6  6  6  6  6  6  6  6  6
 [33]  6  6  6  6  6  6  6  6  6  6  6  6  6  6  6  6  6 12  6  6  6  6  6  6  6 12  6  6  6  6  6  6
 [65]  6  6  6  6  6  6  6  6  6  6  6  6  6  6  6  6  6  6  6  6  6  6  6  6  6  6  6  6  6  6 12  6
 [97]  6  6 12  6  6  6  6  6  6  6  6 12  6  6  6  6  6  6  6  6  6  6  6  6  6  6  6  6  6  2  6  6
[129]  6 12  6  6  6  6  6  6

我使用这个循环得到以下输出：

for (i in num_times)  
  print(months2014[1:i])

[1] "07" "08" "09" "10" "11" "12"
[1] "07" "08" "09" "10" "11" "12"
[1] "07" "08" "09" "10" "11" "12"
[1] "07" "08" "09" "10" "11" "12"
[1] "07" "08" "09" "10" "11" ## repeated upto the 5th element
[1] "07" "08" "09" "10" "11" "12"
[1] "07" "08" "09" "10" "11" "12"
[1] "07" "08" "09" "10" "11" ## repeated up to the 6th element

如果你查看 num_times 向量，它也有 12。因此我也得到了这个结果：

[1] "07" "08" "09" "10" "11" "12" NA   NA   NA   NA   NA   NA

months2014 中只有 6 个元素，所以我得到了 NA。我实际上希望它重新启动并获得如下输出：

[1] "07" "08" "09" "10" "11" "12" "07   "08" "09"   "10"   "11"   "12"

我有三个问题：

1) 如何保存循环输出？我尝试创建一个空向量并将结果放入其中，但这没有用：

temp_vec <- c()
for (i in num_times)  
  temp_vec <- print(months2014[1:i])

2) 如何修复 NA？

3) 一定有更好的方法吗？

Answer 1

经过测试这似乎有效：

sapply(num_times,function(x) rep(months2014,length.out=x)

如果num_times中的值大于months214的长度，则输出一个列表并重复序列：

[[1]]
[1] "07" "08" "09" "10" "11" "12"

[[2]]
[1] "07" "08" "09" "10" "11" "12"

[[3]]
[1] "07" "08" "09" "10" "11" "12"

[[4]]
[1] "07" "08" "09" "10" "11" "12"

[[5]]
[1] "07" "08" "09" "10" "11"

[[6]]
 [1] "07" "08" "09" "10" "11" "12" "07" "08" "09" "10" "11" "12"

重复向量直到第 n 个元素

repeat a vector up to the nth element

loops

r

vector

seq

rep