@extends('template') @section('title') Lab 5, Part 3: Strings with For Loops @stop @section('head') @stop @section('content') # Lab 5, Part 3: Strings with For Loops ## Handling strings A necklace strung with 5 beads. Each bead has a letter on it, and the letters spell out C S 1 1 1.

A necklace strung with 5 beads. Each bead has a letter on it, and the letters spell out C S 1 1 1.

## Table of some string operations:

symbol	operation	example
+	concatenation	str1 = 'I am ' str2 = 'your father ' darth = str1 + str2 yoda = str2 + str1
*	repetition	'hee'*3 ==> 'heeheehee'
[]	index	str2[5]==> 'f'
[:]	slice	str2[2:5]==> 'ur '
in	in	'dad' in str2 ==> False 'at' in str2 ==> True
not in	not in	str1 not in str2 ==> True str1 not in darth ==> False

### A couple of handy string tips: + `yourString[-1]` returns the last letter of a string, eg `'hello'[-1] ==> 'o'` + `.lower()` returns a lowercase version of the given string, eg `'HeLLo.lower() ==> 'hello'` ## Task 1. Writing string functions with loops Continue writing your functions in your `lab05.py` file.

Partner B

1. Write a function called `getWordValue(word)` that takes in a word, and **returns** the value of the word using the following (made-up) rule: Each vowel (a,e,i,o,u) counts as 5 and each consonant counts as 1. You may ignore numbers and special characters for this function. + Here's an `isVowel` function that you can use (or, you can write your own): ```py def isVowel(s): """returns True if s is a vowel; false otherwise""" lowercaseS = s.lower() return lowercaseS in 'aeiou' ``` + Here are some test cases for your `getWordValue` function: ```py print(getWordValue('hello')) ==> 13 print(getWordValue('I')) ==> 5 print(getWordValue('ouch')) ==> 12 print(getWordValue('WELLESLEY')) ==> 21 print(getWordValue('Go 123 Wellesley!!!!')) ==> 27 ```

Partner A

2. Write a function called `starify(word)` that takes in a word, and **returns** a new string with a `*` after each letter in the original word. Hint: create a new string variable, initially empty, that will store the new string to be returned. ```py print(starify('OMG')) ==> O*M*G* print(starify('wicked')) ==> w*i*c*k*e*d* print(starify('Starry')) ==> S*t*a*r*r*y* ``` 3. Write a function called `betterStarify(word)` that takes in a word, and **returns** a new string with a `*` after each letter in the original word, but **not** after the last letter in the word. ```py print(betterStarify('OMG')) ==> O*M*G print(betterStarify('wicked')) ==> w*i*c*k*e*d print(betterStarify('Starry')) ==> S*t*a*r*r*y ```

Partner B

4. In this task, you'll write two functions.
Note that in the box below, you're given a predicate called `starTime` that returns `True` twenty percent of the time and `False` eighty percent of the time.
You can copy/paste the `starTime` predicate below into your `lab05.py` file: ```py import random def starTime(): """returns True 20% of the time; False otherwise. Note: random.random() returns a random number between 0 and 1 """ return random.random() > 0.80 ``` + Write a fruitful function called `makeOneRow` that takes one parameter `rowLength`, and returns a string with length `rowLength` that is made up of stars (`*`) and dashes (`-`). When generating the row, you can use the `starTime` predicate so that 20% of the row is stars. For each spot in the row, use the predicate `starTime`: if it returns `True`, add a star to your row, otherwise, add a dash. Here are some sample invocations of `makeOneRow`: ```py print(makeOneRow(20)) ==> -*------*--*----**-- print(makeOneRow(20)) ==> ----*----*---------- print(makeOneRow(20)) ==> ---***-*--**------*- print(makeOneRow(20)) ==> *--**----*--**--*--- ``` + Write another fruitful function called `starrySky` that takes two parameters: `width` and `height`. `starrySky` returns a string that contains a 'sky' that has `width` and `height` dimensions and each row is created by a call to `makeOneRow`. The sky is built by adding each row and a newline character (`\n`) at the end. Here are some sample invocations: ```py print(starrySky(10, 10)) ==> *-------*- --*------- ---------- ---**----- **--*--*-- --------*- ---------- -----*---- ------*--- --*------- print(starrySky(5, 50)) ==> ----------------**-----**-*----------*---------*-- *--*----*---*---*-----**------*------------*--*--- -*---*---*--------*----------**--------*---*--*--- ---**----*-**---------**---*-------**--*-------*-- ------**-----------------*--------*-----*---*--*-- print(starrySky(3, 60)) ==> --------*-**-**---*---*---------*--*--**-------------------* ----*---------*--*-*--*-**---*----*--------*---*-*----*----* ```

Partner A

5. Write a predicate called `lottaVowels(word)` that **returns** True if the word contains more than 2 vowels. You may use the provided `isVowel` in your `lab05.py` file. ```py print(lottaVowels('OMG')) ==> False print(lottaVowels('hello')) ==> False print(lottaVowels('ABBA')) ==> False print(lottaVowels('GottaLOVEABBA')) ==> True print(lottaVowels('piano')) ==> True print(lottaVowels('eee')) ==> True print(lottaVowels('gummybears')) ==> True print(lottaVowels('laugh')) ==> False print(lottaVowels('laughingxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx')) ==> True ``` Note: look at the last example, with this string 'laughingxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx'. It would be efficient if your `lottaVowels` returned True as soon as the third vowel was encountered, rather than waiting until the end of the string. Can you amend your `lottaVowels` so it does that? (Sometimes we call this 'early exit')

Partner A

6. Write a function called `checkPassword(word)` that takes in a word, and **returns** True if the word satisfies the following password criteria and False otherwise. Hint: Python has some very useful built-in functions such as `islower,isupper` and `isdigit`, for example `'a'.islower()` returns `True` and `'a'.isupper()` returns `False`. - Password must contain a mix of upper and lower case letters - Password must contain at least 1 number - Password must contain at least 1 special character from this set !#$%&\* ```py print(checkPassword('hello123')) ==> False print(checkPassword('PASSWORD')) ==> False print(checkPassword('myPASSWORD?')) ==> False print(checkPassword('loveMyDogCharlie!')) ==> False print(checkPassword('CS111#rocksmyworld')) ==> True print(checkPassword('running99*FAST')) ==> True print(checkPassword('oK8!')) ==> True # Minimum length would be good idea too ```

Partner B

7. [OPTIONAL] Write a function called `ransomNote(sentence)` that takes in a sentence, and **returns** a new sentence, based on the original sentence, with each letter randomly capitalized (with a 50% chance of being capitalized. Might need to use the `random.randint` function). Need a `randint()` refresher? Here is an example from [the previous lab with the coin flip](http://cs111.wellesley.edu/content/labs/solutions/lab04/conditionals.py), and here are the [general python documentation pages for random numbers](https://docs.python.org/3.7/library/random.html). ```py print(ransom("Must provide chocolate to get your teddy bear back")) ==> muST ProvIDE CHocOlATe To get YOur TEddY bEAr bACK print(ransom("Meet me at grand central station with harry styles and a million dollars tonight")) ==> mEET mE at graND CentRAL sTatIOn WITh HarRY StYlEs AND a mIlLIOn DOLLaRs TOnigHT ``` @include('/labs/lab05/_toc') @stop