Homework  Assignment Number 8

• Write a function that add er to the end of a word as follows:
• If the last letter of the word is y, change the last letter to an i before adding er
  
• Double the last letter before adding er if:
• the last letter is b,d,g,l,m,n,p,r,s or t
  
• and the second to last letter is a vowel
• and the word is 2 letters long or the third to last letter is not a vowel
  
• If the last letter of the word is e, just add an r instead of er
• Othewise just add er without changing the word
  
• Assume that there is a single parameter for your function, the word that you want to add er to.
  
• Use regular expressions to identify the different cases.
  
• Examples: bid → bidder, eat → eater, sin → sinner, silly → sillier, sprint → sprinter, bike → biker
• Note: The above rules may not correctly handle all of these examples. See grading criteria below regarding exceptions
  

Grading Criteria

1. Does your programs work?
   
2. Does it solve the problem?
3. Do you use regular expressions?
4. Is your code clearly written?
5. Is it elegant or clever?
6. Optionally, change rules to handle exceptions: coy → coyer, dicey → dicier, dopey → dopier
   
• Please make a note using a comment (to make it clear that you are intentionally varying from the instructions)
  

Note: You can ask any questions by email or in person and I will give you hints if you are having trouble.

What you Should remember:

1. re.search(pattern,string)
• Will return nothing if no pattern is found
• This is treated like False, if used as a boolean expression
2. If a pattern is found, a match object will be returned.
3. There are 3 slots of that object:
• pattern.group(0) is the matched substring
• pattern.start() is the starting position of that substring
• pattern.end() is the ending position
4. You need to use the square brackets to indicate a list of possible letters.
• [abcd] means a or b or c or d
5. You need to use $ to represent the end of the word.
6. You need to create new a new string by slicing and appending.