问题
I am new to R, I want to create a frequency table, I have a data like this,
Member_id Car interest
1 FORD_MUSTANG 4
1 BUICK_Lucerne 1
1 CHEVROLET_SILVERADO 1
2 CHEVROLET_SILVERADO 1
2 FORD_MUSTANG 2
3 FORD_MUSTANG 6
I would like to have a frequency table like this:
MEmber_id FORD_MUSTANG BUICK_Lucerne CHEVROLET_SILVERADO
1 4 1 1
2 2 0 1
3 6 0 0
I have tried using table(Member_id,car), but it returns me values 1 values for each car make.
Appreciate any help.
回答1:
Try
library(reshape2)
dcast(df, Member_id~Car, value.var="interest", fill=0)
# Member_id BUICK_Lucerne CHEVROLET_SILVERADO FORD_MUSTANG
#1 1 1 1 4
#2 2 0 1 2
#3 3 0 0 6
Or
library(tidyr)
spread(df, Car, interest, fill=0)
# Member_id BUICK_Lucerne CHEVROLET_SILVERADO FORD_MUSTANG
#1 1 1 1 4
#2 2 0 1 2
#3 3 0 0 6
If you want to create the columns in the order you specified
df$Car <- with(df, factor(Car, unique(Car)))
spread(df, Car, interest, fill=0)
# Member_id FORD_MUSTANG BUICK_Lucerne CHEVROLET_SILVERADO
#1 1 4 1 1
#2 2 2 0 1
#3 3 6 0 0
data
df <- structure(list(Member_id = c(1L, 1L, 1L, 2L, 2L, 3L), Car = c("FORD_MUSTANG",
"BUICK_Lucerne", "CHEVROLET_SILVERADO", "CHEVROLET_SILVERADO",
"FORD_MUSTANG", "FORD_MUSTANG"), interest = c(4L, 1L, 1L, 1L,
2L, 6L)), .Names = c("Member_id", "Car", "interest"), class = "data.frame", row.names = c(NA,
-6L))
来源：https://stackoverflow.com/questions/26469975/creating-a-frequency-table-in-r