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    Lab 6, Part 2: Strings with For Loops
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# Lab 6, Part 2: Strings with For Loops

Note: Some of you may have done parts of this during Lab05, if so, just skip ahead to functions that you have not yet written.

## Handling strings

<img src="cs111beads.gif" style="width:300px" alt="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:

<table class="ops" style="border:1">

<tbody>

<tr>
   <th>symbol</th>
   <th>operation</th>
   <th>example</th>
</tr>

<tr>
   <td class="up" align="center" style="font-size: 200%;">+</td>
   <td class="up">concatenation</td>
   <td class="up">
      str1 = 'I am '  <br>
      str2 = 'your father '  <br>
      darth = str1 + str2  <br>
      yoda = str2 + str1 <br>
</tr>
<tr>
     <td class="up" align="center" style="font-size: 200%;">*</td>
     <td class="up">repetition</td>
     <td class="up">'hee'*3 ==> 'heeheehee'</td>
</tr>

<tr>
     <td class="up" align="center" style="font-size: 200%;">[]</td>
     <td class="up">index</td>
     <td class="up">str2[5]==> 'f'</td>
</tr>
<tr>
	<td class="up" align="center" style="font-size: 200%;">[:]</td>
	<td class="up">slice</td>
	<td class="up">str2[2:5]==> 'ur '</td>
</tr>
<tr>
	<td class="up" align="center" style="font-size: 200%;">in</td>
	<td class="up">in</td>
	<td class="up">'dad' in str2 ==> False <br>
	     'at' in str2 ==> True</td>
</tr>

<tr>
	<td class="up" align="center" style="font-size: 200%;">not in</td>
	<td class="up">not in</td>
	<td class="up">str1 not in str2 ==> True  <br>
	str1 not in darth ==> False</td>
</tr>
</tbody>
</table>


### 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'`

<a class="anchor" name="Task2Writingmorestringfunctions"></a>


## Task 1. Writing string functions with loops

Create a new file called `lab06.py` and add the functions below to that file.

<div class='partnerB'>Partner B</div>

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. 

   +  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
    # Check that your code works on this one:
    print(getWordValue('Go 123 Wellesley!!!!')) ==> 27
```

<div class='partnerA'>Partner A</div>

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
```

<div class='partnerB'>Partner B</div>

4. In this task, you'll write two functions.  <br>
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.
<br>
You can copy/paste the `starTime` predicate below into your `lab06.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)) ==> 
   --------*-**-**---*---*---------*--*--**-------------------*
   ----*---------*--*-*--*-**---*----*--------*---*-*----*----*
```



<div class='partnerB'>Partner A</div>
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 `lab06.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
```
<span class="note">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')</span>

<div class='partnerA'>Partner A</div>

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
```

<div class='partnerB'>Partner B</div>

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
```

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