问题
I have some issues to change the shape of my df.
Data:
id <- c(1,2,3,4,1,4,1,2,3)
a <- c("A","B","C","D","A","D","A","B","C")
b <- c(1,1,1,1,2,2,3,3,3)
c <- c(12,10,12,23,16,17,7,9,7)
df <- data.frame(id,a,b,c)
which results in:
id a b c
1 A 1 12
2 B 1 10
3 C 1 12
4 D 1 23
1 A 2 16
4 D 2 17
1 A 3 7
2 B 3 9
3 C 3 7
I would like to get the following structure where column b corresponds to month:
id a 1 2 3
1 A 12 16 7
2 B 10 NA 9
3 C 12 NA 7
4 D 23 17 NA
I tried:
df2 <- reshape(df, timevar = "b", idvar = c("id", "a", "c"), direction = "wide")
But that doesn't help much...
回答1:
Try this
library(reshape2)
dcast(df, id + a ~ b, value.var = "c")
# id a 1 2 3
# 1 1 A 12 16 7
# 2 2 B 10 NA 9
# 3 3 C 12 NA 7
# 4 4 D 23 17 NA
Or slightly modifying your solution using reshape
reshape(df, timevar = "b", idvar = c("id", "a"), direction = "wide")
# id a 1 2 3
# 1 1 A 12 16 7
# 2 2 B 10 NA 9
# 3 3 C 12 NA 7
# 4 4 D 23 17 NA
回答2:
Using tidyr
library(tidyr)
spread(df, b, c)
# id a 1 2 3
#1 1 A 12 16 7
#2 2 B 10 NA 9
#3 3 C 12 NA 7
#4 4 D 23 17 NA
来源:https://stackoverflow.com/questions/31134062/reshape-a-data-frame-from-long-to-wide