Introducing Python, 2nd Edition

Appendix D. Answers to Exercises

1. A Taste of Py

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

1.2 Start the Python 3 interactive interpreter. Again, details are in Appendix B. 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 Mac:

$ python
Python 3.7.3 (v3.7.3:ef4ec6ed12, Mar 25 2019, 16:39:00)
[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

2. Data: Types, Values, Variables, and Names

2.1 Assign the integer value 99 to the variable prince, and print it.

>>> prince = 99
>>> print(prince)
99
>>>

2.2 What type is the value 5?

>>> type(5)
<class 'int'>

2.3 What type is the value 2.0?

>>> type(2.0)
<class 'float'>

2.4 What type is the expression 5 + 2.0?

>>> type(5 + 2.0)
<class 'float'>

3. Numbers

3.1 How many seconds are in an hour? Use the interactive interpreter as a calculator and multiply the number of seconds ...