Exam Prep and Wrap-Up Intro to Computer Science CS1510, Section 2 Dr. Sarah Diesburg

Topics for today Information on the exams Questions remaining from Tuesday’s Lab? Several examples from your book Some string formatting examples Split()

Exam Information Two exams next week Focuses on chapters 1-4 Includes material from the lectures and from the readings.

Exam Information Monday, October 14  In class, written exam  Mixture of multiple choice, short answer, and essay.  100 points  Closed book, closed notes

Exam Information Tuesday, October 15  In lab, programming exam  Five small scripts  125 points (25 points each)  Closed book, MOSTLY closed notes One page (one sided) of handwritten notes May also use the built in Python documentation (really not helpful if you haven’t used it before then)

Advice for the Tests These things can make the difference of whether you pass or fail this class when studying  Go through each class days notes and example programs on the website  Practice coding over and over by going through your labs!!! This is the only way to really learn. Review vocabulary and concepts by reading the book!! 6

Again… The only way you can become comfortable with a toolset is to practice  Understanding what a power drill does will not help you much if you don’t practice using it  It’s the same for code  Practicing coding will make you more familiar with the coding structures necessary to code more quickly  Patterns will emerge, it will become easier 7

Questions about Tuesday’s Lab Did you understand the explanations I made on both the string-based and math-based solutions? Remaining issues?

Questions over PA05? 9

Anything you want me to go over? 10

String Wrap-Up Find a Letter Enumerate Split Palindromes

4.1 Find a Letter river = 'Mississippi' target = input('Input character to find: ') for index in range(len(river)): #for each index if river[index] == target: #check print( "Letter found at index: ", index ) break # stop searching else: print( 'Letter',target,'not found in',river)

Enumerate Function The enumerate function prints out two values: the index of an element and the element itself Can use it to iterate through both the index and element simultaneously, doing dual assignment

Enumeration # print first occurrence river = 'Mississippi' target = input('Input character to find: ') for index,letter in enumerate(river): if letter== target: #check print ("Letter found at index: ", index) break # stop searching else: print( 'Letter',target,'not found in',river)

Enumeration # print all occurrences river = 'Mississippi' target = input('Input character to find: ') for index,letter in enumerate(river): if letter== target: #check print ("Letter found at index: ", index ) # break # stop else: print( 'Letter',target,'not found in',river)

Split Function The split function will take a string and break it into multiple new string parts depending on what the argument character is. By default, if no argument is provided, split is on any whitespace character (tab, blank, etc.) You can assign the pieces with multiple assignment if you know how many pieces are yielded.

Reorder a Name origName = ‘John Marwood Cleese’ first,mid,last = origName.split() name = last + ‘, ‘ + first + ‘ ‘ + mid print (name)

Palindromes and the Rules A palindrome is a string that prints the same forward and backwards Same implies that:  case does not matter  punctuation is ignored “Madam I’m Adam” is thus a palindrome

Lower Case and Punctuation Every letter is converted using the lower method Import string, brings in a series of predefined sequences (string.digits, string.punctuation, string.whitespace) We remove all non-wanted characters with the replace method. First arg is what to replace, the second the replacement.

Part 1 of Palindrome # first part import string originalString = input('Input a string:') modifiedStr = originalString.lower() badChars = string.whitespace + string.punctuation for char in modifiedStr: if char in badChars: # remove bad modifiedStr = modifiedStr.replace(char,'')

Part 1 of Palindrome # second part if modifiedStr == modifiedStr[::-1]: # palindrome ? print( 'The original string is: {}\n\ the modified string is: {}\n\ the reversal is: {}\n\ The string is a palindrome'.format( originalString, modifiedStr, modifiedStr[::-1])) else: # similar printing for not a palindrome