Exercises based on Labs, to review for the final 

**Lab3:

Quiz: Finish the following two versions of contains1:

def contains1(c,s):
    '''c is a char and s is a str.   Return True if s contains c
       and false otherwise. '''
    for i in s:
       if i == c:


def contains2(c,s):
    '''c is a char and s is a str.   Return True if s contains c
       and false otherwise. '''

    found = False
    for i in s:
       if i == c:


**Lab4:


#1. At least one of the four potions is poisonous
def hint1(p1, p2, p3, p4):
    return p1 or p2 or p3 or p4

#2. p2 is not poisonous
def hint2(p2):
    return not p2 

#3. At least one of p1 and p3 is poisonous
def hint3(p1,p3):
    return p1 or p3

#4. At least one of p3 and p4 is not poisonous
def hint4(p3,p4):
    return not p3 or not p4

#5. Exactly one of p1, p3, and p4 is poisonous
def hint5(p1, p3, p4):
    return (p1 and not p3 and not p4) or\
           (p3 and not p1 and not p4) or\
           (p4 and not p1 and not p3) 

def solution(p1, p2, p3, p4):
    h1 = hint1(p1, p2, p3, p4)
    h2 = hint2(p2)
    h3 = hint3(p1, p3)
    h4 = hint4(p3, p4)
    h5 = hint5(p1, p3, p4)
    return h1 and h2 and h3 and h4 and h5

for p1 in [True,False]:
    for p2 in [True,False]:
        for p3 in [True,False]:
            for p4 in [True,False]:
                if solution(p1,p2,p3,p4):
                    print (p1,p2,p3,p4, "is a solution!")

#
#Output this produces:
#True False False False is a solution!
#False False True False is a solution!
#

Great exercise for booleans

-- p4 True means that potion 4 is poisonous
-- solution is true if all hints evaluate to True
-- Quiz: 
      
      what does h1(False,False,False,False) evaluate to?


      what does h4(False,True) evaluate to?


** Lab5 

   student_grades = [['999888777', 78.0], ['111222333', 90.0], ['444555666', 83.0]]    

   # Here is an example of a nested loop.  TODO: Run and trace this until you are sure you understand it
   for student in student_grades:
       print(student)
       for x in student:
          print(x)

-- Quiz: Trace on paper/board:

     student:  

     x:
     
   # Now we'll start using a list of measurements
   measurements = [[33, 34, 30], [29, 31, 34], [28, 27, 30]]

   # TODO Write code here to print the average of each inner list
   # For example, for 'measurements', the averages are 32.333333, 31.333333, and 28.333333
   print ("about to print the average of each inner list")
   for dataset in measurements:
       total = 0.0
       for datapoint in dataset:        
           total = total + datapoint
       print("the average of the values in",dataset, "is", total / len(dataset))

-- Quiz:  Trace on paper/board

    dataset:

    total:
   

   # TODO Now do the same thing, but using the builtin function "sum".
   # enter 'help(sum)' in the Shell to see how to use it.

   print("about to print the average of each inner list...again")
   for dataset in measurements:
       print("the average of the values in", dataset, "is", sum(dataset) / len(dataset))

   # TODO read the header and docstring for function 'where' (below).
   # Here, create a set of at least 5 test cases for 'where' and call 'grade'
   # as in lab3 (grade is below).  Then, write function 'where' and test it.


   grade(where('abcdeddw x','d'),3)
   grade(where('a','a'),0)
   grade(where('abcdeddw x','x'),9)
   grade(where('abcdeddw x','z'),-1)
   grade(where('','z'),-1)



def where(s,c):
    '''Given string s and single-character string c, return the
    position of the first occurrence of c in s.  If c is not in s,
    return -1.'''

    # Do not use any string methods, but you can use functions in __builtins__
    #
    # Remember that the positions of strings and list are numbered, starting
    #   at 0.  s = 'next'; s[0] is 'n'; s[1] is 'e'; and so on.
    #
    if not c in s:
        return -1
    else:
        for i in range(len(s)):
            if s[i] == c:
                return i

-- Quiz: Trace on board/paper

   s: 'abc'    c: 'b'


   i:

   String method that does this:  'abc'.find('b')

** Lab6

-- Quiz

>>> l = [[12.0,1.0,3.0],[2.0,3.0],[66.1,77.1]]
>>> l[0]

>>> l[1]

>>> l[2]

>>> l[0][0]

>>> l[0][2]

>>> l[2][0]

>>> l[2][1]

>>> 

-- Added some print statements to the solution to show what is
   happening at each point

def inputTemperatureData(filename):
    '''Open the specified filename,
    read past the three-line header, read in the temperature data on
    the file, and close the file.  Return the temperature data in the
    form of a list of lists, where each list element is a list of 12
    temperature readings.'''

    # Hint: use readline to read the first three lines, and then
    # a while loop to read the numbers
    #
    # Hint: you need to convert the input from strings to
    #  to floats.

    f = open(filename)
    f.readline()
    f.readline()
    f.readline()

    data = []
    line = f.readline()
    while line != "":
        nums = line.split()
        flt_nums = []
        for n in nums:
            flt_nums.append(float(n))
        data.append(flt_nums)
        line = f.readline()
    f.close()

    return data

def printDataPoint(tempData,mo,yr):
    '''tempData is the data structure returned
    by inputTemperatureData.  mo is an integer in the range 0 to 11.
    yr is in the range 0 to len(tempData) - 1.  Print the temperature
    for that month and that year.  Suppose mo is 1 and yr is 3.
    The output should look like this (assuming the value is 65.7):
    The ave. monthly temperature during Feb in year 4 is 65.7. '''

    mos = ['Jan', 'Feb', 'Mar', 'Apr', 'May', 'June', 'July', 'Aug', 'Sept', 'Oct', 'Nov', 'Dec']
    print("The ave. monthly temperature during",mos[mo],"in year",yr,"is",
          format(tempData[yr][mo],".2f"))

--- Having a list of months might be useful for printing elsewhere;
    better than a big if-elif statement
        
def avgTempMarch(tempData):
    '''Return the average temperature for the month of March as a float 
    for all years in tempData. tempData is the data structure returned
    by inputTemperatureData.'''

    total = 0
    for year in tempData:
        total += year[2]
    return float(total)/len(tempData)    

--- The structure of tempData is [[data for year 0][data for year 1]...]

--- year:   [the 12 values for a single year]
--- year[3]:   the march value for that year     
--- len(tempData) is the number of years for which we have data

def avgTemp(tempData, mo):
    '''Return the average temperature for month mo as a float for all
    years in tempData, where mo is an integer
    between 0 and 11, representing January to December,
    respectively. tempData is the data structure returned
    by inputTemperatureData.'''

    total = 0
    for year in tempData:
        total += year[mo]
    return float(total)/len(tempData)    

--- Just like the above, except that 'mo' is a parameter


def higherAvgTemp(tempData, mo1, mo2):
    '''Return either mo1 or mo2 (integers representing months in the
    range 0 to 11), whichever has the higher average temperature for
    all years in tempData.  If the months have the 
    same average temperature, then return -1. tempData is the data structure returned
    by inputTemperatureData.'''



def avgTemps (tempData):
    ''' Return the average of all the temperatures stored in tempData. tempData is the
    data structure returned by inputTemperatureData.'''

    total = 0
    for year in tempData:
        for mo in year:
            total += mo
    return float(total)/(len(tempData) * 12)        


** Lab7

>>> s1 = "I poured Spot remover on my dog."
>>> s2 = "Now he's gone."
>>> s1[4:9]
'ured '
>>> s2[-1]
'.'
>>> s2[:7]
"Now he'"
>>> s1[6:]
'ed Spot remover on my dog.'
>>> s1[:3] + s1[4:]
'I pured Spot remover on my dog.'
>>> lst = [1,2,3]
>>> help(list.extend)
Help on method_descriptor:

extend(...)
    L.extend(iterable) -- extend list by appending elements from the
    iterable

>>> lst.extend([44,55])
>>> lst
[1, 2, 3, 44, 55]
>>> lst.extend(range(2,5))
>>> lst
[1, 2, 3, 44, 55, 2, 3, 4]
>>> lst.extend("Dog")
>>> lst
[1, 2, 3, 44, 55, 2, 3, 4, 'D', 'o', 'g']
>>> lst.remove(44)
>>> lst.remove(55)
>>> lst
[1, 2, 3, 2, 3, 4, 'D', 'o', 'g']
>>> lst = []
>>> lst1 = [0,1,2]
>>> lst2 = ["Spot","remover"]
>>> lst3 = [[3,4],[5,6]]
>>> lst.append(lst1)
>>> lst
[[0, 1, 2]]
>>> lst.append(lst2)
>>> lst
[[0, 1, 2], ['Spot', 'remover']]
>>> lst.append(lst3)
>>> lst
[[0, 1, 2], ['Spot', 'remover'], [[3, 4], [5, 6]]]
>>> lst[1]
['Spot', 'remover']
>>> lst[2]
[[3, 4], [5, 6]]
>>> lst[3]
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
IndexError: list index out of range
>>> lst[2]
[[3, 4], [5, 6]]
>>> lst[2][0]
[3, 4]
>>> lst[2][0][1]
4
>>> 

Write code that inputs an int between 1 and 5 from the user, and
creates a list called "lst" that contains that many empty lists.  For
example, if the user enters 3, your code should create [[],[],[]].

>>> num = int(input("Enter an int between 1 and 5 "))
>>> lst = []
>>> for i in range(num):
...   lst.append([])
... 
>>> lst
[[], [], []]

--- Trace:
i:

lst:

>>> board = []
>>> for i in range(3):
...   row = []
...   for col in range(3):
...      row.append("*")
...   board.append(row)
... 
>>> board

What is printed here? 

>>> 

--- For the following, make sure you can see which variables change
    their values

>>> def fun1(s):
...    s * 3
...    return None
... 
>>> s1 = "You're unique like everyone else"
>>> fun1(s1)
>>> s1
"You're unique like everyone else"
>>> def fun2(s):
...    return s * 3
... 
>>> s1 = fun2(s1)
>>> s1
"You're unique like everyone elseYou're unique like everyone
elseYou're unique like everyone else"
>>> def fun3(lst):
...    lst.append("construction")
... 
>>> x = [3,4,5]
>>> fun3(x)
>>> x
[3, 4, 5, 'construction']
>>> 



>>> d = [["knock knock","who's there"],["cash","cash who?"],["No
    thanks, but I would like a peanut instead","Groan"]]
>>> d
[['knock knock', "who's there"], ['cash', 'cash who?'], ['No thanks,
    but I would like a peanut instead', 'Groan']]
>>> person1 = 0
>>> person2 = 1
>>> for i in d:
...   print("P1:",i[person1])
...   print("P2:",i[person2])
...   print()
... 
P1: knock knock
P2: who's there

P1: cash
P2: cash who?

P1: No thanks, but I would like a peanut instead
P2: Groan