Have a look at the dataframe (df) below.

I would like to alphabetically order the content of the modules column. Desired output:

To achieve said result I have tried the following:

df[lapply(strsplit(as.character(df$Modules), ','), sort)),]

Without succes sadly. What fundamental mistake do I make?

CodePudding user response：

collapse the sorted string back into one string using toString.

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

data

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")

CodePudding user response：

you could use order i guess?

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