Lists (Arrays)

Lists are used to hold a list of elements. They could be strings, numbers, etc. Normally, you would use an array type, but python does not support arrays.

list.py

# create a list of car names
cars = ['Ford', 'Nissan', 'Toyota']

# access first car name
car = cars[0]
print(f'The first car is {car}')

# how many cars are there
print(f'There are {len(cars)} cars')

# print all the cars
print('Cars:')
for car in cars:
    print(car)
print('-----')

# add a car to the list
cars.append("Honda")

print('Cars after append(Honda):')
for car in cars:
    print(car)
print('-----')

print("Done.")

Output:

The first car is Ford
There are 3 cars
Cars:
Ford
Nissan
Toyota
-----
Cars after append(Honda):
Ford
Nissan
Toyota
Honda
-----
Done.

Links

• Python Arrays

Exercises (5 mins)

1. Use a for loop to find a user number in a list.

   find_a_number.py

   numbers = [10, 15, 20, 25, 30, 35]
   
   # Enter a number
   
   # Convert the number to a int
   
   # Set a flag to false
   
   for number in numbers:
       if number == :
           found = True
   
   if found == True:
       print("Found the number in the list.")
   else:
       print("Sorry, did not find the number.")
   
   print('Done.')
   

   Output:

   Enter a number: 20
   Found the number in the list.
   Enter a number: 22
   Sorry, did not find the number.
   

2. Use a for loop to sum all the numbers in a a list.

   sum_numbers.py

   numbers = [10, 15, 20, 25, 30, 35]
   
   # intialize a sum to 0
   
   for number in numbers:
       # add the numbers in the list
   
   # print the sum
   
   print('Done.')
   

   Output:

   The sum is 135
   

3. Find the smallest and largest number in a list.

   sum_numbers.py

   numbers = [0, 2, 5, 100, -1, 4, 8, -5 ]
   
   # intialize smallest to the first element of the list
   
   # initialize largest to the first element of the list
   
   for number in numbers:
       # find the smallest number
       # find the largest number
   
   # print the smallest number
   # print the largest number
   
   print('Done.')
   

   Output:

   The smallest number is -5
   The largest number is 100