Introducing Python

Appendix E. Answers to Exercises

Chapter 1, A Taste of Py

1.1 If you don’t already have Python 3 installed on your computer, do it now. Read Appendix D for the details for your computer system.

1.2 Start the Python 3 interactive interpreter. Again, details are in Appendix D. It should print a few lines about itself and then a single line starting with >>>. That’s your prompt to type Python commands.

Here’s what it looks like on my MacBook Pro:

$ python
Python 3.3.0 (v3.3.0:bd8afb90ebf2, Sep 29 2012, 01:25:11)
[GCC 4.2.1 (Apple Inc. build 5666) (dot 3)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>>

1.3 Play with the interpreter a little. Use it like a calculator and type this: 8 * 9. Press the Enter key to see the result. Python should print 72.

>>> 8 * 9
72

1.4 Type the number 47 and press the Enter key. Did it print 47 for you on the next line?

>>> 47
47

1.5 Now type print(47) and press Enter. Did that also print 47 for you on the next line?

>>> print(47)
47

Chapter 2, Py Ingredients: Numbers, Strings, and Variables

2.1 How many seconds are in an hour? Use the interactive interpreter as a calculator and multiply the number of seconds in a minute (60) by the number of minutes in an hour (also 60).

>>> 60 * 60
3600

2.2 Assign the result from the previous task (seconds in an hour) to a variable called seconds_per_hour.

>>> seconds_per_hour = 60 * 60
>>> seconds_per_hour
3600

2.3 How many seconds are in a day? Use your seconds_per_hour