# An Introduction to Python¶

## Lists¶

### This notebook contains the programming exercises for An Introduction to Python: Lists.¶

References:

• Fundamentals of Python Programming. Halterman, Richard. Southern Adventist Univesity. 2018.

# Exercises¶

## Do the following problems.¶

### Jupyter Notebook Shortcuts:¶

There are two modes when a cell is highlighted.

#### Command Mode: Press ESC to activate. The cell has a blue border if this mode is active. In this mode, you can add, delete, create, copy and paste cells.¶

• create a new cell above the current cell: a
• create a new cell below the current cell: b
• delete the current cell: dd
• change the current cell’s type to “Code”: y
• change the current cell’s type to “Markdown”: m

#### Edit Mode: Press ENTER to activate. The cell has a green border if this mode is active. In this mode, you can edit and type text into the cell.¶

• execute the current cell and create a new cell: SHIFT + ENTER

#### Create a list of 5 string objects representing different types of foods. Use a for loop to iterate over the list and print the objects separated by spaces.¶

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#### Use the list created in the previous problem and demonstrate the use of append, remove and pop by adding to, removing from and popping elements from the list.¶

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#### Given the list lst = [20, 1, -34, 40, -8, 60, 1, 3] evaluate the following expressions. Write your answers in markdown first then use code to verify your answer.¶

• lst[0:3]
• lst[4:8]
• lst[-5:-3]
• lst[4:]
• lst[:]
• lst[:4]
• lst[1:5]
• -34 in lst
• -34 not in lst
• len(lst)

#### Create the following list: [1,2,3,4,5,6,7,8]. Use slicing to obtain the following sublists:¶

• [2,3,4,5]
• [1,3,5,7]
• [1,2,3,4,5,6] (use negative indices for this problem)
• [1,2,3,4,5,6,7,8]
• [8,7,6,5,4,3,2,1]
• [6,5,4,3]
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#### Create an empty list.¶

1) Then use a for loop to append to the list the multiples of 3 from 12 to 2340. Print out the length of this list.

2) Redo part 1) of this problem but use list comprehensions instead of a for loop.

3) Use list comprehension as in part 2) but add in the additional condition that the numbers need to be a multiple of 7.

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#### Use the built-in function list() and the range() function to create a list of even numbers from 2 to 50.¶

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#### Use sum to find the sum of a list created in the previous problem.¶

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#### Write the list represented by each of the following list comprehension expressions. Write your answers in markdown then check with code.¶

• [x + 1 for x in [2, 4, 6, 8]]
• [10*x for x in range(5, 10)]
• [x for x in range(10, 21) if x % 3 == 0]

#### Suppose lst = [-2,4,6,-4,-5,12,-7,5,3]. Use list comprehension to extract the positive numbers from the list.¶

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#### Write a segment of code that asks the user to input a positive integer n. Use list comprehension to create a list factors which is a list of factors of n.¶

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#### Without running the following code, can you tell what it does for a given integer n? (Pretty cool!)¶

[x for x in range(2, n) if n % x == 0] == []


#### Create a list where each element of the list is another list of a student name(string) and a gpa(float). Your list should have 4 student-gpa pairs. Then use a nested loop to print out each student name and gpa, each on a different line.¶

One sample output:

Mike 2.3
John 3.5
Michele 3.7
Carol 3.2

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