How to convert dot to comma for numerical columns in an R data frame?

Most European countries use a comma in place of a decimal. Therefore, if we have a data set that contains dot as a decimal market and we need to use that four such European countries or if dot is recorded in place of comma then we can replace the dot with comma using format function as shown in the below examples.

Example1

x2<−sample(c(501.24,502.7,501.24,503.2),20,replace=TRUE)
y2<−sample(c(2.24,2.7,1.4,3.2),20,replace=TRUE)
df2<−data.frame(x2,y2)
df2

Output

   x2     y2
1 503.20 1.40
2 502.70 2.24
3 503.20 2.70
4 503.20 3.20
5 502.70 2.24
6 503.20 2.24
7 502.70 2.24
8 501.24 1.40
9 502.70 1.40
10 501.24 2.70
11 502.70 2.24
12 502.70 3.20
13 503.20 2.70
14 502.70 2.70
15 502.70 3.20
16 503.20 2.70
17 503.20 1.40
18 502.70 1.40
19 501.24 1.40
20 502.70 2.70

Replacing dots with comma −

Example

format(df2,decimal.mark=",")

Output

   x2     y2
1 503,20 1,40
2 502,70 2,24
3 503,20 2,70
4 503,20 3,20
5 502,70 2,24
6 503,20 2,24
7 502,70 2,24
8 501,24 1,40
9 502,70 1,40
10 501,24 2,70
11 502,70 2,24
12 502,70 3,20
13 503,20 2,70
14 502,70 2,70
15 502,70 3,20
16 503,20 2,70
17 503,20 1,40
18 502,70 1,40
19 501,24 1,40
20 502,70 2,70