Hi@akhtar,
You can use the select method to extract any columns from a data frame. I have attached one example below for your reference.
> df
IND snp1 snp2 snp3 snp4 snp5
1 1 A/G T/T T/C G/C G/G
2 2 A/A C/C G/G G/G A/A
3 3 T/T G/G C/C C/C T/T
This is a data frame that has six columns. Now to extract particular columns we can use the select method.
> select(df, snp1,snp3,snp4)
snp1 snp3 snp4
1 A/G T/C G/C
2 A/A G/G G/G
3 T/T C/C C/C