How to extract specific columns from a DataFrame

Question

Sample data frame:

df<-as.data.frame(matrix(sample(1:10,100,replace=TRUE),10))
   V1 V2 V3 V4 V5 V6 V7 V8 V9 V10
1   8  9  3  2  4  5  8  8  6   5
2   2  4  5  7  4  6  6  2  4   3
3   1  5  4 10  8 10 10  3  5   2
4  10  7 10  7  2  8  2  3  8  10
5   1  7  4  5  1  3  3  2  1   4
6   4  7  3  4  5  4  1  2  4   5
7  10 10  7  9  5 10  3 10  7   1
8   7  5  2  2  5  6 10 10  4   6
9   3  2 10  2  4  8  3  2  9   7
10  8  6  6  9  9  4  8 10  3   6

Now if I want V2 and V4 ?

data.frame(df$V2,df$V4)

But I want more accurate and compact way!

Answer 1

Yes there are so many ways:

df[,c(V2,V4)]

and another way

By using subset()

subset(df,select=c(V2,V4))