Overview
     day one                                day four
         0. introduction                         7.  files, programs and user 
         1. text output and manipulation            input
         2. reading and writing files            8.  biopython
     today                                  day five 
         3. lists and loops                         hands on training
         4. writing functions                       feedback and discussion
     day three
                                                  Etherpad for today:
         5.  conditional statements      http://python-from-scratch.pad.spline.de/2
         6.  dictionaries
    This course (apart from chapter 8) is based on the book "Python for Biologists":
                                            
           http://pythonforbiologists.com/ 
                                   from scratch
      A primer for scientists working with Next-Generation-
                        Sequencing data 
                        CHAPTER 3
                        lists and loops
                                  
    Chapter 3: lists and loops
    lists and loops help us deal with these issues:
     ● performing tasks repeatedly for multiple, similar objects
     ● usually not possible to know the number of data items
     ● necessary for dealing with large datasets
                                     
    Dealing with repetitive tasks
    often the same task needs to be performed repeatedly for a 
    set of similar objects with only slight variation for each 
    object
    lists can hold a variable number of elements
    loops enable running the same commands multiple times