How to convert more than one column in R data frame to from integer to numeric in a single line code?

To convert columns of an R data frame from integer to numeric we can use lapply function. For example, if we have a data frame df that contains all integer columns then we can use the code lapply(df,as.numeric) to convert all of the columns data type into numeric data type.

Example1

Consider the below data frame −

 Live Demo

set.seed(871)
x1<−sample(0:1,20,replace=TRUE)
x2<−sample(0:5,20,replace=TRUE)
x3<−sample(1:5,20,replace=TRUE)
x4<−sample(0:9,20,replace=TRUE)
x5<−sample(1:10,20,replace=TRUE)
df1<−data.frame(x1,x2,x3,x4,x5)
df1

Output

x1 x2 x3 x4 x5
1 0 2 2 9 9
2 0 2 1 1 10
3 1 1 5 8 10
4 1 3 2 4 3
5 0 0 2 4 3
6 1 5 2 8 3
7 0 4 5 4 5
8 1 1 5 8 1
9 0 1 4 9 7
10 0 4 2 0 9
11 1 1 4 7 6
12 0 2 4 8 5
13 1 5 5 0 1
14 1 0 1 5 4
15 0 0 3 7 5
16 1 0 4 6 4
17 1 5 4 7 8
18 1 1 1 3 2
19 1 2 3 6 3
20 0 0 1 8 1

str(df1)

Output

'data.frame': 20 obs. of 5 variables:
$ x1: int 0 0 1 1 0 1 0 1 0 0 ...
$ x2: int 2 2 1 3 0 5 4 1 1 4 ...
$ x3: int 2 1 5 2 2 2 5 5 4 2 ...
$ x4: int 9 1 8 4 4 8 4 8 9 0 ...
$ x5: int 9 10 10 3 3 3 5 1 7 9 ...

Converting columns of df1 to numeric −

df1<−lapply(df1,as.numeric)
str(df1)

Output

List of 5
$ x1: num [1:20] 0 0 1 1 0 1 0 1 0 0 ...
$ x2: num [1:20] 2 2 1 3 0 5 4 1 1 4 ...
$ x3: num [1:20] 2 1 5 2 2 2 5 5 4 2 ...
$ x4: num [1:20] 9 1 8 4 4 8 4 8 9 0 ...
$ x5: num [1:20] 9 10 10 3 3 3 5 1 7 9 ...

Example2

 Live Demo

y1<−rpois(20,10)
y2<−rpois(20,8)
y3<−rpois(20,5)
y4<−rpois(20,2)
df2<−data.frame(y1,y2,y3,y4)
df2

Output

y1 y2 y3 y4
1 9 10 4 3
2 6 9 4 0
3 7 9 3 4
4 4 3 6 1
5 9 7 2 4
6 17 4 7 2
7 6 5 7 0
8 3 5 5 4
9 12 6 7 5
10 15 10 4 2
11 6 3 5 2
12 9 10 6 0
13 6 8 6 2
14 11 6 4 2
15 9 7 3 5
16 12 7 3 3
17 18 9 8 4
18 7 5 3 5
19 14 4 7 4
20 17 8 8 3

Example

str(df2)

Output

'data.frame': 20 obs. of 4 variables:
$ y1: int 9 6 7 4 9 17 6 3 12 15 ...
$ y2: int 10 9 9 3 7 4 5 5 6 10 ...
$ y3: int 4 4 3 6 2 7 7 5 7 4 ...
$ y4: int 3 0 4 1 4 2 0 4 5 2 ...

Converting columns of df2 to numeric −

df2<−lapply(df2,as.numeric)
str(df2)

List of 4
$ y1: num [1:20] 9 6 7 4 9 17 6 3 12 15 ...
$ y2: num [1:20] 10 9 9 3 7 4 5 5 6 10 ...
$ y3: num [1:20] 4 4 3 6 2 7 7 5 7 4 ...
$ y4: num [1:20] 3 0 4 1 4 2 0 4 5 2 ...

Example3

 Live Demo

z1<−sample(21:30,20,replace=TRUE)
z2<−sample(1:50,20)
z3<−sample(101:200,20)
df3<−data.frame(z1,z2,z3)
df3

Output

z1 z2 z3
1 29 32 130
2 27 26 149
3 22 11 199
4 30 28 161
5 21 36 174
6 29 8 152
7 23 23 142
8 27 22 114
9 24 45 135
10 21 34 171
11 28 40 125
12 24 42 148
13 21 43 106
14 25 1 137
15 26 7 118
16 22 2 184
17 28 4 192
18 24 38 183
19 27 31 168
20 21 3 185

Example

str(df3)

Output

'data.frame': 20 obs. of 3 variables:
$ z1: int 29 27 22 30 21 29 23 27 24 21 ...
$ z2: int 32 26 11 28 36 8 23 22 45 34 ...
$ z3: int 130 149 199 161 174 152 142 114 135 171 ...

Converting columns of df3 to numeric −

df3<−lapply(df3,as.numeric)
str(df3)

Output

List of 3
$ z1: num [1:20] 29 27 22 30 21 29 23 27 24 21 ...
$ z2: num [1:20] 32 26 11 28 36 8 23 22 45 34 ...
$ z3: num [1:20] 130 149 199 161 174 152 142 114 135 171 ...