1

我要重复的向量是：

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

我想根据定义第 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

我使用这个循环来获得以下输出：

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

如果您查看 num_times 向量，它也有 12 个。因此，我也得到以下结果：

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

里面只有 6 个元素，months2014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，但这不起作用：

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

2）如何修复 NA ？

3）必须有更好的方法来做到这一点？

4

1 回答 1

4

经过测试，这似乎有效：

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

如果 in 的值num_times高于 的长度，它会输出一个列表并重复该序列months214：

[[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"
于 2016-10-07T17:00:23.780 回答