Dictionary and Set Lab

Learning about dictionaries and sets

Goal:

Learn the basic ins and outs of Python dictionaries and sets.

Procedure

Create a new dict_lab.py file.

The file should be an executable Python script. That is to say that one should be able to run the script directly like so:

$ ./dict_lab.py

(on OS-X and Linux) or

$ py dict_lab.py

(on Windows)

To make this work you, make sure you include the ‘shebang’ on the first line of your file.

#!/usr/bin/env python3

Finally (on OS-X and linux) you need to make the file executable; do that with this command:

$ chmod +x dict_lab.py

(The +x means make this executable)

Add the file to your clone of the repository and commit changes frequently while working on the following tasks.

When the script is run, it should accomplish the following four series of actions:

Dictionaries 1

  • Create a dictionary containing “name”, “city”, and “cake” for “Chris” from “Seattle” who likes “Chocolate” (so the keys should be: “name”, etc, and values: “Chris”, etc.)

  • Display the dictionary.

  • Delete the entry for “cake”.

  • Display the dictionary.

  • Add an entry for “fruit” with “Mango” and display the dictionary.

    • Display the dictionary keys.

    • Display the dictionary values.

    • Display whether or not “cake” is a key in the dictionary (i.e. False) (now).

    • Display whether or not “Mango” is a value in the dictionary (i.e. True).

Dictionaries 2

  • Using the dictionary from item 1: Make a dictionary using the same keys but with the number of ‘t’s in each value as the value (consider upper and lower case?).

    The result should look something like:

    {"name": 0
 "city": 2
 "cake": 2
}

Sets

  • Create sets s2, s3 and s4 that contain numbers from zero through twenty, divisible by 2, 3 and 4 (figure out a way to compute those – don’t just type them in).

  • Display the sets.

  • Display if s3 is a subset of s2 (False)

  • and if s4 is a subset of s2 (True).

Sets 2

  • Create a set with the letters in ‘Python’ and add ‘i’ to the set.

  • Create a frozenset with the letters in ‘marathon’.

  • Display the union and intersection of the two sets.