Lab: Random Sequences

In this lab, you will write code to generate random character sequences.

Instructions

You should complete this lab individually.

Background

In class, we used the product rule to count the number of possible sequences:

The Generalized Product Rule: Let $S$ be a set of sequences of length $k$. Suppose that there are $n_1$ choices for the first element of a sequence, $n_2$ for the second, …, and $n_k$ for the kth element. Then $|S| = n_1 \cdot n_2 \cdot \ldots \cdot n_k$

Your code will use the product rule to count the number of possible sequences for a user-specified format.

Implementation

Write a Python program sequences.py which accepts a user-specified sequence format. The sequence format is a string consisting of three special characters:

• d represents a digit
• a represents a lowercase alphabetic character (a-z)
• A represents an uppercase alphabetic character (A-Z)

These special characters should be replaced by randomly chosen characters. All other characters should remain unchanged.

First, your program should calculate the total number of possible sequences. Next, your program should print three example sequences. For example:

> python sequences.py d
10 possibilities. For example:
2
2
8

> python sequences.py aaAAdd
45697600 possibilities. For example:
nkVF03
maYO52
acMZ35

> python sequences.py "(ddd) ddd-dddd"
10000000000 possibilities. For example:
(132) 000-3056
(852) 711-1016
(623) 187-7081

You may find these Python modules helpful:

• random
• secrets
• string

Submit

Upload sequences.py to Gradescope.

Learning Goals

• Count using the product rule
• Use randomness in Python