I have a file of SNPs that was processed using plink. Is there an easy method to remove the monomorphic snps from the file using plink? or is this best done using python. I have a list of several thousands of snps and in the file they are assigned either an NA, 0, 1, or 2. I want to remove the list of snps that have an NA i.e. they are monomorphic. The problem is that the file lists all of the multiple thousands of snps in order and then lists there respective values after than in one line seperated by spaces so it is very hard to see what values correspond to which snp based on manual inspection. The goal again is to remove snps that are valued at na using plink hopefully; python as a last resort. Thanks Bob