subset with pattern

Question

Say I have a data frame df

df <- data.frame( a1 = 1:10, b1 = 2:11, c2 = 3:12 )

I wish to subset the columns, but with a pattern

Answer 1

Same same but different:

df2 <- df[, grep("1", names(df))]
   a1 b1
1   1  2
2   2  3
3   3  4
4   4  5
5   5  6
6   6  7
7   7  8
8   8  9
9   9 10
10 10 11