问题
I have a medium large dataframe, for which I want to transform one column with categories to binary columns, one for each category.
At the same time, I want to keep the rest of the columns in the dataframe.
What would be the easiest way to achieve this?
Here is an example of what I want to do:
d<-data.frame(ID=c("a","b","c","d"), Gender=c("male", "male", "female","female"), Age =c(23,45,18,11))
ID Gender Age
1 a male 23
2 b male 45
3 c female 18
4 d female 11
should look as d2 afterwards, so that the ID and Age columns are still there and untouched:
d2<-data.frame(ID=c("a","b","c","d"), Gender.male=c(1, 1, 0, 0), Gender.female=c(0,0,1,1), Age =c(23,45,18,11))
ID Gender.male Gender.female Age
1 a 1 0 23
2 b 1 0 45
3 c 0 1 18
4 d 0 1 11
回答1:
We can use spread
library(tidyvesre)
d %>%
mutate(n = 1) %>%
spread(Gender, n, fill = 0)
回答2:
Or use dcast from reshape2
library(reshape2)
dcast(d, ID + Age ~ Gender, length)
# ID Age female male
#1 a 23 0 1
#2 b 45 0 1
#3 c 18 1 0
#4 d 11 1 0
回答3:
We can use the dummies package.
library(dummies)
d2 <- dummy("Gender", d)
d3 <- cbind(d, d2)
d3$Gender <- NULL
d3
# ID Age Genderfemale Gendermale
# 1 a 23 0 1
# 2 b 45 0 1
# 3 c 18 1 0
# 4 d 11 1 0
来源：https://stackoverflow.com/questions/50972807/transform-one-column-from-categoric-to-binary-keep-the-rest