I have a large file of TCGA hm450 methylation data that I want to filter to only see the samples I'm interested in. At first, I output just the column header to understand the format of the file. I noticed that they're sample barcodes, some with decimal points on the end. For example: TCGA-G5-6572-01A-11D-1828-05.2 and TCGA-G5-6572-01A-11D-1828-05.3.
What does the decimal point on the end mean? There's some documentation available about how sample barcodes should be interpreted, but none that I've found mention this. Is it something specific to these experiments?
EDIT: as @igor pointed out, these are multiple columns referencing the same samples. I didn't notice before because I was constrained to looking at a small part of the data due to the sheer size of it, but there are separate columns for Gene_Symbol, Chromosome, Genomic_Coordinate etc for each sample.
