Lecture 1 - Exercises

The exercises for Lecture 1 are available under Quick Links to the left. And here, for convenience.

 Example Ruby File

The Ruby code in the file "probesPerGene.rb" below is an example of putting a bunch of Ruby code into a file so it can be run on demand. I ran it by doing this at the command line:

ruby ./probesPerGene.rb

It will look for a file named "methylationProbeInfo.lff" in the same dir (you can get this by uncompressing methylationProbeInfo.lff.gz provided below). Then it does this:

1. Reads each line of the file, which is a probe definition record
   
2. Extracts the gene name associated with the probe
3. Keeps track, using a Hash, how many probes are associated with each gene
4. Once the file has been processed, it writes a tab-delimited text file with two columns: (a) the gene name and (b) the number of probes associated with the gene.
5. (the output file is called "probesPerGene.txt" and is included below; running the program should generate this file).
   

The code is commented using lines beginning with "#". Ruby will ignore such lines, allowing you to comment code to explain to yourself and others what the code is doing.