Question about changes and bugfixes on episodes 1, 2, 7 and 10

[mpaegert]

Changes and bugfixes on episodes 1, 2, 7 and 10

1. I changed a few things in the mentioned episodes, do you want them as one pull-request or per episode?
2. If accepted, would this count as certification as instructor?

List of changes:

Episode 1

After the first "type" command I added a short callout "Classes and Objects". All "type" outputs will start with "<class ...>" and there is no mentioning anywhere what a "class" is. Added a class entry to the reference as well. This may make the the episode about 1 to 2 minutes longer.

Episode 2

Loading the data into variable "data", then printing it. This saves time to repeat numpy.loadtxt later on.

Added sneak peek to episode 3 by letting matplotlib plot the data in order to get an overview. This should illustrate the power of the library concept and motivate for the rather dry part about indexing and slicing following it.

Together with the introduction of class in episode 1, students now better understand the output of "print(type)data))" - .

Slicing: added not "row index comes first". This is not clearly stated anywhere else.

Adding a clarifying note about "axis = 0" and "axis = 1" after fig/python-operations-across-axes.png.

These changes do not make the episode longer.

Episode 7

"Checking our Data" needs to restore 'data' from previous episode if this is a new interpreter session. Added that and comments in the second block of source code.

Episode 10

Wrong error in first 2 error-boxes of "Test-Driven Development": you do not get an AssertionError, but a NameError instead as the function range_overlap has not been written yet.