r语言 - 按字母顺序对单元格的内容进行排序

Question

看一下下面的数据帧(df)

<表类> 日期 模块 26-11-2021 NA, Advanced chemistry, Biochemistry 25-11-2021 食品物理、食品化学

我们可以用tidyr中的separate_rows

library(dplyr)
library(tidyr)
df1 %>% 
separate_rows(Modules, sep = ",\s*") %>% 
arrange(Date, Modules) %>%
group_by(Date) %>% 
summarise(Modules = toString(Modules))
# A tibble: 2 × 2
Date       Modules                             
<chr>      <chr>                               
1 25-11-2021 Food chemistry, Food physics        
2 26-11-2021 Advanced chemistry, Biochemistry, NA

数据

df1 <- structure(list(Date = c("26-11-2021", "25-11-2021"),
Modules = c("NA, Advanced chemistry, Biochemistry", 
"Food physics, Food chemistry")), row.names = c(NA, -2L), class = "data.frame")

使用toString将排序后的字符串折叠成一个字符串。

df$Modules <- sapply(strsplit(as.character(df$Modules), ',\s*'), 
function(x) toString(sort(x)))
df
#        Date                              Modules
#1 26-11-2021 Advanced chemistry, Biochemistry, NA
#2 25-11-2021         Food chemistry, Food physics

df <- structure(list(Date = c("26-11-2021", "25-11-2021"), 
Modules = c("NA, Advanced chemistry, Biochemistry", 
"Food physics, Food chemistry")), 
row.names = c(NA, -2L), class = "data.frame")

我猜你可以使用顺序?

v<-c("Z","X","Y","A","B","C")
df<-data.frame(1:6,v)
> df[order(df$v),]
X1.6 v
4    4 A
5    5 B
6    6 C
2    2 X
3    3 Y
1    1 Z