反转列中的值

问题描述

我的数据是这样的。我想反转 B 列的值。

df <- data.frame(A = c(  "Not at all","Several days","More than half the days","Nearly every day "),B = c(1,2,3,4))

所以，我想要这样。

df <- data.frame(A = c(  "Not at all",B = c(4,1))

rev 不适用于我的数据，数据的结构是：

'data.frame':   511 obs. of  6 variables:
 $ id...1          : int  1 2 3 4 5 6 7 8 9 10 ...
 $ Q3.2_1...2      : num  1 3 2 2 2 2 2 2 3 2 ...
 $ id...3          : int  1 2 3 4 5 6 7 8 9 10 ...
 $ Q3.2_1...4      : chr  "Several days" "Not at all" "Not at all" "Nearly every day" ...
 $ newcolumn.id    : int  1 2 3 4 5 6 7 8 9 10 ...
 $ newcolumn.Q3.2_1: chr  "Several days" "Not at all" "Not at all" "Nearly every day" 

我想反转 Q3.2_1 编号。

解决方法

试试这个：

#Code
df$B <- rev(df$B)

输出：

df
                        A B
1              Not at all 4
2            Several days 3
3 More than half the days 2
4       Nearly every day  1

或使用dplyr：

library(dplyr)
#Code
df <- df %>% mutate(B=rev(B))