Allen Codingbat Exercises

These Codingbat exercises were super simple and really straight forwards and were good practice and probably good for retaining of what we've learned so far

Warmups

Warmup Checklist

I completed the Warmups.

Strings

Warmup Checklist

I completed the Strings

Lists

Warmup Checklist

I completed the Lists

Logic

Warmup Checklist

I completed the Logic!

It was hard oming up with three exercises that were interesting. Weirdly enough the warmup problems were more difficult than any of the other sections. Which made them more interesting to me.The warmup questions dealing with strings were little more difficult for me. So I preferred them.

front3

Given a string, we'll say that the front is the first 3 chars of the string. If the string length is less than 3, the front is whatever is there. Return a new string which is 3 copies of the front.

I like this problem because of just how deceptively simple it is. The entire problem can be summed up in a single line of code.



def front3(str):
    return str[:3]*3

print front3("kitten")

missing_char

Given a non-empty string and an int n, return a new string where the char at index n has been removed. The value of n will be a valid index of a char in the original string (i.e. n will be in the range 0..len(str)-1 inclusive).

We did a similar problem for the interactive textbook. In this case you are just removing a letter. I like these problems, because the easiest way to do it is to think of it as printing the string without the letter you want, rather than thinking of it as "removing" the letter.

def missing_char(str, n):
  front = str[:n]   
  back = str[n+1:] 
  return front + back

Output:

missing_char('kitten', 1) → 'ktten'
missing_char('kitten', 0) → 'itten'
missing_char('kitten', 4) → 'kittn'

not_string

Given a string, return a new string where "not " has been added to the front. However, if the string already begins with "not", return the string unchanged.

This question is similar to the previous ones. In this case you are looking at a string to see if it starts with "not" if it doesn't you simply add "not" to the start of the string. It was also deceptively simple.

def not_string(str):
  if str[:3] == "not":
    return str
  return "not " + str

Output:

not_string('candy') → 'not candy'
not_string('x') → 'not x'
not_string('not bad') → 'not bad'

That's my stuff!

SILShack Spring 2014