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How to find the column maximum if some columns are categorical in R data frame?
To find the column maximum if some columns are categorical in R data frame, we can follow the below steps −
First of all, create a data frame.
Then, use numcolwise function from plyr package to find the column maximum if some columns are categorical.
Example 1
Create the data frame
Let’s create a data frame as shown below −
Group<-sample(c("I","II","III","IV"),25,replace=TRUE)
Num1<-sample(1:50,25)
Num2<-sample(1:50,25)
df1<-data.frame(Group,Num1,Num2)
df1Output
On executing, the above script generates the below output(this output will vary on your system due to randomization) −
Group Num1 Num2 1 III 43 36 2 I 5 22 3 IV 3 23 4 II 40 40 5 IV 47 33 6 II 12 3 7 II 31 21 8 IV 34 20 9 I 41 44 10 II 7 8 11 II 35 45 12 III 50 25 13 III 19 16 14 III 11 34 15 I 1 28 16 III 21 31 17 IV 9 47 18 III 15 9 19 I 23 11 20 III 45 24 21 I 37 26 22 I 13 32 23 I 27 30 24 II 2 10 25 I 48 12
Find the column maximum if some columns are categorical
Using numcolwise function from plyr package to find the column maximum of numerical columns in the data frame df1 −
Group<-sample(c("I","II","III","IV"),25,replace=TRUE)
Num1<-sample(1:50,25)
Num2<-sample(1:50,25)
df1<-data.frame(Group,Num1,Num2)
library(plyr)
numcolwise(max)(df1)Output
Num1 Num2 1 50 47
Example 2
Create the data frame
Let’s create a data frame as shown below −
Categories<-sample(c("First","Second","Third"),25,replace=TRUE)
Score<-sample(1:10,25,replace=TRUE)
Price<-sample(1:5,25,replace=TRUE)
df2<-data.frame(Categories,Score,Price)
df2Output
On executing, the above script generates the below output(this output will vary on your system due to randomization) −
Categories Score Price 1 Third 6 1 2 Second 7 1 3 Second 5 5 4 First 8 3 5 Third 5 2 6 First 9 2 7 Third 6 5 8 First 9 4 9 First 4 1 10 Second 4 5 11 Second 2 1 12 First 9 3 13 Second 4 3 14 First 4 2 15 Third 5 4 16 Third 2 5 17 First 1 4 18 First 2 1 19 Third 2 5 20 Second 1 1 21 Third 7 1 22 Second 4 2 23 First 10 1 24 Third 6 4 25 First 8 4
Find the column maximum if some columns are categorical
Using numcolwise function from plyr package to find the column maximum of numerical columns in the data frame df2−
Categories<-sample(c("First","Second","Third"),25,replace=TRUE)
Score<-sample(1:10,25,replace=TRUE)
Price<-sample(1:5,25,replace=TRUE)
df2<-data.frame(Categories,Score,Price)
library(plyr)
numcolwise(max)(df2)Output
Score Price 1 10 5
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