Functions 6

This is a follow up to Strings 6.

A colleague has produced a file with one DNA sequence on each line. Download the file and load it into Python using numpy.loadtxt(). You will need to use the optional argument dtype=str to tell loadtxt() that the data is composed of strings.

Calculate the GC content* of each sequence by writing a function that takes a dna sequence as input and returns the GC-content of that sequence. Print the result for each sequence. Before we knew about functions we had to take each dna sequence one at a time and then rewrite or copy-paste the same code to analyze each one. Isn’t this better?

* The GC content is the percentage of bases that are either G or C (as a percentage of total base pairs).