# How to find the column minimum if some columns are categorical in R data frame?

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To find the column minimum 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 minimum if some columns are categorical.

## Example

#### 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)
df1

## Output

On executing, the above script generates the below output(this output will vary on your system due to randomization) −

   Group Num1 Num2
1   IV   45   19
2  III   37    5
3  IV    21   27
4  III   16   26
5  III   34   48
6   I     3   11
7  II    49   10
8   I    24    8
9   I    26   25
10  II   20   49
11  I    29   29
12  II    8   12
13  I     7   31
14 III   44   38
15 III    2   20
16 III   23   37
17  I    15   15
18  I    42   45
19  I    11   47
20 IV     6   40
21 II    41    3
22 II    48   14
23 III   31   24
24 IV    13   17
25 II     5   41

Find the column minimum if some columns are categorical

Using numcolwise function from plyr package to find the column minimum 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(min)(df1)

## Output

  Num1 Num2
1   2   3

## 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)
df2

## Output

On executing, the above script generates the below output(this output will vary on your system due to randomization) −

    Categories Score Price
1  Third        8     1
2  First        8     1
3  Second       8     3
4  Second       8     2
5  Third        1     1
6  Second       1     1
7  First        5     3
8  Third        5     3
9  First        4     1
10 Second       6     3
11 Third        6     3
12 Third        2     4
13 Second       7     4
14 First        5     3
15 Second       1     4
16 Third        1     5
17 Third        7     4
18 Third       10     4
19 Third        1     3
20 Second       4     3
21 Second       3     1
22 Second      10     4
23 First        3     5
24 First        1     4
25 Second       6     4

Find the column minimum if some columns are categorical

Using numcolwise function from plyr package to find the column minimum 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(min)(df2)

## Output

  Score Price
1   1    1
Updated on 09-Nov-2021 05:56:37