Non-Lab 6: Strings

Goals

After the non-lab, you should be proficient at

solving basic string problems using methods, loops, and the substring operator

Objective: Review

Review the slides for today.

Objective: Linux

As usual, create a directory for the programs and output you develop in this lab in your cs111 directory.

Objective: Help Client Set Up

Run runHelpClient

Objective: Programming in Python

We'll practice writing several Python programs, each in their own text file. Name the files as lab6_x.py, where x is the problem number.

Your programs will be graded on correctness, style, efficiency, and how well you tested them. Make sure you adhere to the good development and testing practices we discussed in class. Your code should be readable and your output should be useful and well-formatted. I am getting tougher on these criteria as we develop larger programs.

After you've developed a correct solution to each program, restart IDLE or close and reopen the IDLE "shell" by running the program again (using F5), demonstrate that the program works using several good test cases, and save the output to a file named lab6_x.out, where x is the problem number.

The next two problems are to focus on problem-solving with strings. You don't need to create functions for these problems.

(15) Translate a string into pirate speak. Write a program that takes a string as input, converts that string to pirate speak, and displays it.

To convert a string to pirate speak, replace every 'r' in the string with 'rrr'. (You don't need to worry about uppercase R's, just lowercase.) For example:
```
Enter a string to convert to pirate speak: hello there, friends.
hello therrre, frrriends. 
```
```
Enter a string to convert to pirate speak: generals
generrrals
```
If the string doesn't have the letter 'r' in it, add an ', arrrr' to the end of the string to make it more pirate like.
```
Enter a string to convert to pirate speak: washington and lee
washington and lee, arrrr
```
(Did you know that programming had such practical uses?)
(15) Web servers and Web browsers need to know a file's type so they know how to display the file. The file's type is based on the file name's extension. For example, we name our Python scripts with the .py extension and our HTML files with the .html extension.
In the Python interpreter, run help(str). Look at how to use the rfind method and compare that with how the find method is used.
Then, use the rfind method to determine any file's type based on its name. Handle error cases appropriately.
Example output:
```
What is the name of your file? index.html
index.html is a html file.  
```
```
What is the name of your file? picture.jpg
picture.jpg is a jpg file.  
```
```
What is the name of your file? 15.strings.pdf
15.strings.pdf is a pdf file.
```
(15) Download/copy the pick4winner.py file and save as lab6_3.py. Refactor the code such that it has a function called generateWinningNumber that takes no parameters and returns a generated winning number. (Why can't we use the testEqual function to test this function?) Then, put the other, non-constants/non-imports code into main and call main. Demonstrate that your code works.

Extra Credit (up to 7 pts)

Sometimes, lotteries pay out money for getting a few matches (the correct number in the same spot). For example, if the user guessed "1244" and the winning number is "1784", then the user had two correct numbers in the same spot (the first number and the last number) and maybe wins a little bit of money.

Copy your pick4winner.py (that you refactored above) and name it lab6_ec.py.

Modify it such that it reports how many numbers the user matched. If the user matched 2 or 3 numbers, congratulate the user on getting some numbers correct.

Include error handling to make sure that the user enters a valid number.

A solution that makes good use of functions will receive more credit.

**************************************************
This program simulates the Pick 4 VA Lottery game
**************************************************

What is your guess for the Pick 4 number (in format ####)? 1234
The Pick 4 Winner is 8272
You lose!  Good thing you didn't bet any money.

**************************************************
This program simulates the Pick 4 VA Lottery game
**************************************************

What is your guess for the Pick 4 number (in format ####)? 123
Your pick does not have enough digits

**************************************************
This program simulates the Pick 4 VA Lottery game
**************************************************

What is your guess for the Pick 4 number (in format ####)? 1234
The Pick 4 Winner is 0232
You had 2 digits right! Here's a bit of cash.

Finishing up: What to turn in for this lab

Note that each command links to a page with more information about using the command.

Create the printable lab assignment, using the createPrintableLab command:
createPrintableLab <labdirname>
View your file using the evince command.
Submit your lab directory into your turnin directory.
Log out of your machine when you are done.

Labs are due at the beginning of Friday's class.

Ask well before the deadline if you need help turning in your assignment!

Grading (45 pts)

Python programs: 45 pts; see above for breakdown