Exercises

Exercise 7

Save your code in your Python folder and call it exercise7.

Write a program that:

creates a first list [2,8,5,4,6,7,8,5]
creates a second list [3.5, 'coucou', 8, 'hello', 6.2]
inserts the value 3 in the first list between the values 2 and 8
adds the value 72 at the end of the second list
removes 'coucou' from the second list
combines both lists using the extend method
prints the final list
prints the value at index 5 of the list
prints the 4 first elements of the list
prints the 3 last elements of the list
prints the elements starting at index 2 and ending at index 5 included

At the end of the exercise, you should get the following output:

📋 Output

>>> %Run Ex7.py
[2, 3, 8, 5, 4, 6, 7, 8, 5, 3.5, 8, 'hello', 6.2, 72]
6
[2, 3, 8, 5]
['hello', 6.2, 72]
[8, 5, 4, 6]
>>>

Help

To create a list, assign its content to a variable: variable = [1,2,3].
my_list.insert(2, 'c') will insert the letter 'c' at the index 2 of my_list.
my_list.append(56) will add 56 at the end of my_list.
my_list1.extend(my_list2) will insert my_list2 at the end of my_list1.
del(my_list[1]) will remove the element at the index 1 from my_list.
my_list.remove(32) will remove the element 32 from my_list.
You can directly access an element from a list using the index method: my_list[index] and you can modify it.
It is possible to select part of a list by writing: my_list[start_index:end_index]
- If you don’t specify the start_index, Python will assume that it is 0.
- If you don’t specify the end_index, Python will assume that it is the last index of the list.

Exercise 8

Save your code in your Python folder and call it exercise8.

Write a function total(list_number) that receives a list of number and returns the sum of all those numbers. For example, if the list given in parameter is [1,2,3], it should return 6.

Then write a program that:

Repeatedly asks numbers to the user and add them to a list until the user enters stop.
Once stop is entered, calls the function total(list_number) with the list of number as parameter.
Prints the result returned by the function.

Help

To repeatedly ask a number to the user until the user enters stop, you can use the following code:

🐍 Python Script

listOfNumbers = []
askAgain = True
while askAgain == True:
    answer = input("Give me a number (or write stop if you are done): ")
    if answer == "stop":
        askAgain = False
    else:
        listOfNumbers.append(int(answer))

Show the complete answer

🐍 Python Script

def total(list_numbers):
    total = 0
    for number in list_numbers:
        total += number
    return total

listOfNumbers = []
askAgain = True
while askAgain == True:
    answer = input("Give me a number (or write stop if you are done): ")
    if answer == "stop":
        askAgain = False
    else:
        listOfNumbers.append(int(answer))

print(total(listOfNumbers))

Exercise 9

Save your code in your Python folder and call it exercise9.

Write a function largestNumber(list_number) that receives a list of number and returns the largest number from the list. For example, if the list given in parameter is [1,2,10,3], it should return 10.

Then write a program that:

Repeatedly asks numbers to the user and add them to a list until the user enters stop.
Once stop is entered, calls the function largestNumber(list_number) with the list of number as parameter.
Prints the result.

Help

To get the largest number from a list, you should:

Initialise a variable to 0;
Go through the list using a for loop;
At each cycle of the loop check if the current item is bigger than the value saved in your variable. If it is, replace the value in the variable by the current value, if it isn't, do nothing.

The largest number from the list will be saved in the variable.

Exercise 10

Save your code in your Python folder and call it exercise10.

Write a function size(list_strings) that receives a list of strings and returns how many of those strings are 5 or more letters. For example, if the list given in parameter is ['abcdef', 'xyz', 'aba', '1221221221'], it should return 2.

Then write a program that:

Repeatedly asks words to the user and adds them in a list until the user enters stop.
Once stop is entered, calls the function size(list_strings) with the list of words as parameter.
Prints the result.

Help

To check the length of a string, you use the len() function.

Exercise 11

Save your code in your Python folder and call it exercise11.

Write a function checkZero(list_number) that receives a list of number and returns True if there is a zero in the list, False otherwise. For example, if the list given in parameter is [1,2,3], it should return False. If the list is [3,6,9,0,3], it should return True.

Then write a program that:

Repeatedly asks numbers to the user and add them to a list until the user enters stop.
Once stop is entered, calls the function checkZero(list_number) with the list of number as parameter.
Prints the result.

Exercise 12

Save your code in your Python folder and call it exercise12.

Write a function occurrences(list_letters, letter) that receives a list of letters and a letter as parameters and returns two things: how many times the letter appears in the list of letters and a list with the indexes where it appears. For example, if the list given in parameter is [“a”,”e”,”b”,”a”] and the letter given in parameter is “a”, it should return: 2 and [0,3]

Then write a program that:

Repeatedly asks letters to the user and add them to a list until the user enters stop.
Once stop is entered, asks the user to pick one letter.
Calls the function occurrences with the list of letters and the letter as parameters.
Prints the following:

📋 Output

The letter appears 2 times.
It appears at the following index: [0, 3].

Help

To return more than one variable, you can write the return like that: return (variable1, variable2). When you call your function, you will save whatever is returned in a variable, for example result. Then you can get the value saved in variable1 by writing result[0] and the value saved in variable2 by writing result[1].

Example

🐍 Python Script

def example():
    a = 8
    b = "coucou"
    return (a,b)

x = example()
print (x[0]) # will print 8
print (x[1]) # will print "coucou"