#!/usr/bin/env python
# coding: utf-8

# # Lecture 2, Part 2 Exercises 

# ## ***Before starting, please run the following cell***

# In[ ]:


from __future__ import division, print_function 


# ## Question 1

# Write a function that takes in a list and returns the length of the list. Fill in the function definition below.

# In[3]:


def listLen(l):
    #write here


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print(listLen([1, 2, 3]) == 3)
print(listLen(["Daniel","Basi", "Mike", "Leello", "Rupal"]) == 5)
print(listLen([]) == 0)


# ## Question 2

# ### 2.1

# What is the last number printed in this example:

# ```python
# for elem in [23, 42, 10]:
#     print(elem)
# ```

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# How about in this example?

# ```python
# for elem in range(10):
#     print(elem + 5)
# ```

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# How if at all, is this different from the previous example?

# ```python
# for elem in range(0, 10):
#     print(elem + 5)
# ```

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# Is the last element printed in this example different from the last element printed in the above example?

# ```python
# for elem in range(0, 10, 2):
#     print(elem + 5)
# ```

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# ### 2.2

# Using a for loop print every element in the list l. Do this using 
# 
# 1) for x in l syntax
# 
# 2) for x in range syntax

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l = [2,7,5]
# write for loop here with method 1

# use method 2 here


# ### 2.3

# Write a function ```printNums(x)``` that prints every number between $0$ and $x-1$. 
# 
# For example when $x = 3$, ```printNums(x)``` should give:
# ```
# 0
# 1
# 2
# ```

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# Write code here


# ### 2.4

# Write a function ```sumx(x)```, using a for loop, that sums every number between $0$ and $x - 1$ inclusive. Hint: you may want to define a variable inside your function to keep track of the running sum. 
# 
# For example, with $x = 5$
# ```python
# sumx(x)
# ```
# would return $10 (= 0+1+2+3+4)$.

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print(sumx(4)==10)
print(sumx(0)==0)
print(sumx(10)=55)


# ## Question 3

# ## 3.1

# Write a function ```first(l)``` that takes in a list and returns the first element of the list.

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print(first([1,1,2,3,5,8,13])==1)
print(first(["Hello","please","print","the","first", "word"])=="Hello")
print(last([42, 10, 15, 50])==42)


# ## 3.2

# Write a function ```last(l)``` that takes in a list and returns the last element of the list.

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print(last([1,1,2,3,5,8,13])==13)
print(last(["Hello","please","print","the","last", "word"])=="word")
print(last([42, 10, 15, 50])==50)


# ## 3.3

# Using calls to the functions above, write a function ```extreme(l)``` that takes in a list (`l`) and returns the sum of the first and last element of the list. If the list has length less than 1 return a string saying "Not possible".
# 

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print(extreme([1,2,3]) == 4)
print(extreme([0,2,4,0]) == 0)
print(extreme([0]) == "Not possible")


# ## Question 4

# Write a function ```sum(l)``` that given a list returns the sum of all the elements in the list.
# 
# ```python
# sum([]) = 0
# sum([1,2,3]) = 6
# ```
# 
# First do this using `for x in l` syntax.

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print(sum([]) == 0)
print(sum[1, 2, 3] == 6)
print(sum[10, 20, 30, 5, 1] == 66)


# Now do this without using the `for x in l` syntax. 

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print(sum([]) == 0)
print(sum[1, 2, 3] == 6)
print(sum[10, 20, 30, 5, 1] == 66)


# ## Question 5

# Write a function ```oddval(l)``` that prints all the odd numbers in a list.
# 
# For example:
# ``` python
# oddval([5, 2, 8, 17, 32, 2, 8, 9])
# ```
# should print:
# 
# ``` python
# 5
# 17
# 9
# ``` 

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print("Test1:")
oddval([5, 2, 8, 17, 32, 2, 8, 9])

print("Test2:")
oddval([10, 0, 3, 8, 6, 8])

print("Test3:")
oddval([1, 2, 3, 4, 5, 6])


# ## Question 6

# Write a function ```oddind(l)``` that prints all the values in odd indices.
# 
# For example: 
# ``` python
# oddind([1, 2, 3, 4, 9, 15])
# ``` 
# should print:
# ``` python
# 2
# 4
# 15
# ```

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print("Test1:")
oddind([1, 2, 3, 4, 9, 15])

print("Test2:")
oddval([5, 2, 8, 17, 32, 2, 8, 9])

print("Test3:")
oddval([10, 0, 3, 8, 6, 8])

print("Test4:")
oddval([123, 234, 345])


# ## Question 7

# Write a function ```isPrime(x)``` that given integer x will return ```True``` if `x` is prime and ```False``` otherwise.
# 
# Formally, $x$ is prime if and only if for all $1<i<x$, $(x$ ``` 
# mod 
# ``` 
# $ i) \neq 0$.

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# Write code here


# Run the cell below to test your `isPrime(x)` function.

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def test():
    inputs = [1, 2, 25, 11, 13, 51]
    expected_output = [False, True, False, True, True, False]
    for i in range(len(inputs)):
        if (isPrime(inputs[i]) != expected_output[i]):
            print("Failed on input: ", inputs[i])
            return
    print("All test cases passed!")
    

test()


# ## Question 8

# What does the following code print?

# ```python
# for i in range(3):
#     for j in range(3):
#         print([i, j])
# ```

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# ## Question 9

# In this problem you will be dealing with a set of temperatures over a week represented as floats in a list. After you complete each of the subproblems run the test cell to verify your solution.

# ### 9.1

# Given a list of temperatures in a week, write a function ```findMin(l)``` that takes in such a list of floats and returns the minimum temperature in the list.

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# Write code here


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def test():
    #list of test cases
    inputs = [[13.25,14.11,15.64,20.53,17.32,18.63,14.90],
              [-1.34,0.0,5.89,6.73,2.54,4.53,7.01],
              [5.53,2.63,0.7,8.26, 10.1, 6.13,2.43],
              [7.98,12.34,10.52,13.64,15.42,14.42,16.32],
              [8.42,12.542,13.25,17.52,15.24,10.45,8.86]]
    expected_output = [13.25, -1.34, 0.7, 7.98, 8.42]
    for i in range(len(inputs)):
        if (findMin(inputs[i]) != expected_output[i]):
            print("Failed on input: ", inputs[i])
            return
    print("All test cases passed!")
            
test()


# ### 9.2

# Now find the average temperture of each week. So given a list of temperatures, write a function ```findAvg(l)``` that returns the average temperature of the list using for loop(s).

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# Write code here


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def test():
    #list of test cases 
    inputs = [[13.25,14.11,15.64,20.53,17.32,18.63,14.90],
              [-1.34,0.0,5.89,6.73,2.54,4.53,7.01],
              [5.53,2.63,0.7,8.26, 10.1, 6.13,2.43],
              [7.98,12.34,10.52,13.64,15.42,14.42,16.32],
              [8.42,12.542,13.25,17.52,15.24,10.45,8.86]]
    expected_output = [16.34, 3.6228571428571428, 5.111428571428571, 12.94857142857143, 12.325999999999999]
    for i in range(len(inputs)):
        if (abs(findAvg(inputs[i]) - expected_output[i]) > 0.1):
            print("Failed on input: ", inputs[i])
            return
    print("All test cases passed!")
            
test()


# ### 9.3

# Now you are given a list of 5 cities' temperatures in a certain week. The first is Addis, second is Harar, followed by Lalibela, Aksum, and Gondar. Write a function ```coldestCity(l)``` that takes in a list of lists, where each list contains 7 floats, and returns the index of the city with the minimum average temperature. Then, write the city name corresponding to that index in the cell provided below the test function.
# 
# Hint: It may be useful to call ```findMin``` and  ```findAvg```  in this function. 

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# Write code here


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def test():
    temps = [[13.25,14.11,15.64,20.53,17.32,18.63,14.90],
              [-1.34,0.0,5.89,6.73,2.54,4.53,7.01],
              [5.53,2.63,0.7,8.26, 10.1, 6.13,2.43],
              [7.98,12.34,10.52,13.64,15.42,14.42,16.32],
              [8.42,12.542,13.25,17.52,15.24,10.45,8.86]]
    expected_output = 1
    if coldestCity(temps) != expected_output:
        print("Test Failed")
    else:
        print("All test case!")
            
test()


# City Name: (write as a string)

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# ## Question 10

# Write a function ```mostCommon(s)``` that takes in a string and returns the most common character in a string. If no character occurs more often than any other character, return any character in the string.
# 
# For example ```mostCommon("salaam")``` should give "a".
# 
# Something like ```mostCommon("aabbbcddeeeee")``` should give "e".
# 
# Something like ```mostCommon("abc")``` could give "a", "b", or "c". 

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# Write code here


# Run the cell below. If what you wrote is correct it should output : "TEST CASES PASSED !"

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# Test cases

def test():
    tests = ["aaa", "The quick Brown Fox jumped over the lazy Fox", "bdabbbd", "bbbacedddde"]
    answers = ['a', ' ', 'b', 'd']
    for i in range(len(tests)):
        if mostCommon(tests[i]) != answers[i]:
            print("TEST CASE FAILED")
            break
    print("TEST CASES PASSED !")
    
test()


# ## Question 11

# Write a function `removeCharacter(s, c)` that given a string (`s`) and a character (`c`), removes all the instances of character `c` in `s`. So this function will return a modified string.
# 
# For example `removeCharacter("hello", "e") = "hllo"`
# 
# Another example `removeCharacter("hello", "f") = "hello"`

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# Write code here


# Run the cell below. If what you wrote is correct it should output : "You've Done Well Friend!"

# In[1]:


def test():
    tests = [("hello world", "h"), ("Jessica", "c"), ("ThunderStick", "r")]
    answers = ['ello world', 'Jessia', 'ThundeStick']
    if [removeCharacters(*x) for x in tests] == answers:
        print("You've Done Well Friend!")
    else:
        print("Errors ! Errors ! Errors!")