# Initialize Otter
import otter
grader = otter.Notebook("hw8-strings.ipynb")

🏡📝 Homework 8#

This assignment includes three problems on the topic of strings.

Question 1: Remove non alpha characters

In this lab you will write a function which takes in a string and removes all of the non-alphabetic characters from it.

Write python code to do the following:

  • Define a function called remove_non_alpha that takes an input string s

  • Loop through each character in the string, adding it to an output string if it is an alphabetic character.

  • Return the final string.

Your code replaces the prompt: ...

...

grader.check("q1-nonalpha")

Question 2: Palindrome Detector

A palindrome is a word or a phrase that is the same when read both forward and backward. Examples are: “bob,” “sees,” or “never odd or even” (ignoring spaces). Write a program whose input is a word or phrase, and that outputs true if the input is a palindrome, otherwise false. In determining if a string is a palindrome, you should treat upper vs. lower case versions of characters as the same letter, and you may ignore all spaces.

Write python code to do the following:

  • Define a function called is_palindrome that takes in one input parameter x.

  • Convert the string x to be all lower case.

  • Remove all spaces from string x. (Hint: use the string.replace method)

  • Loop through the characters of x to determine if it is palindromic

Your code replaces the prompt: ...

...

grader.check("q2-palindrome")

Question 3: Count characters

Your task is to write a function that takes in a character and a string and retruns the count of how many times that character appears in the string.

Write python code to do the following:

  • Define a function called count_characters which takes two arguments, a character c, and a string s

  • Your function should loop through the string and character by character, counting every time the character c is encountered

  • Return the total count, or 0 if the character c is not part of string s

Your code replaces the prompt: ...

...

grader.check("q3-countchars")