r语言 - 如何在包含NAs行的数据框中翻转连续的两行?

Question

我有这个数据框(但非常大，包括许多行在name变量保存值yes没有和)

df = data.frame(name = c('a','b','c',NA,NA,'yes','no',NA,NA,'f','g','h'),
Freq = c(10,20,70,NA,NA,40,60,NA,NA,80,10,10) )

# output
name Freq
1     a   10
2     b   20
3     c   70
4  <NA>   NA
5  <NA>   NA
6   yes   40
7    no   60
8  <NA>   NA
9  <NA>   NA
10    f   80
11    g   10
12    h   10

对于每两个包含的连续行，yes没有和在name列中，我希望它们被翻转成如下格式:

# output
name Freq
1     a   10
2     b   20
3     c   70
4  <NA>   NA
5  <NA>   NA
6    no   60
7   yes   40
8  <NA>   NA
9  <NA>   NA
10    f   80
11    g   10
12    h   10

感谢您的帮助

Answer 1

一种方法如下:

• 检查哪些行包含相邻的yes/no值
• 创建一个索引向量，交换这些行数
• 使用此向量重新排序数据

df = data.frame(name = c('a','b','c',NA,NA,'yes','no',NA,NA,'f','g','h','no','yes'),
Freq = c(10,20,70,NA,NA,40,60,NA,NA,80,10,10,20,20) )
# first find the adjacent rows containing 'yes' and 'no'
# i.e. row contains yes/no & next row contains yes/no & they are not the same
rows <- which(
df$name %in% c('yes','no') &
c(df[-1, 'name'],NA) %in% c('yes','no') & 
df$name != c(df[-1,'name'],NA)
)
# next, swap the row with the next row for each of these by creating an index 
#     variable with these numbers swapped
index <- 1:nrow(df)
index[rows]<-rows+1
index[rows+1] <- rows
df <- df[index,]
print(df)
name Freq
1     a   10
2     b   20
3     c   70
4  <NA>   NA
5  <NA>   NA
7    no   60
6   yes   40
8  <NA>   NA
9  <NA>   NA
10    f   80
11    g   10
12    h   10