Coding Python Final Exam

What data structure is immutable?

Tuple

What data structure uses square brackets []?

List

What data structure uses parentheses ()?

Tuple

What data structure stores key-value pairs?

Dictionary

What does len() return?

The number of items in a list, tuple, string, or other collection

What does append() do?

Adds one item to the end of a list

What does extend() do?

Adds all items from another collection to a list

What does remove() do?

Removes a specified value from a list

What does sort() do?

Sorts a list in ascending order

What does reverse() do?

Reverses the order of items in a list

What is indexing?

Accessing elements by their position number

What is the first index in a list?

0

What does a negative index do?

Counts from the end of the list

What does list[-1] return?

The last item in the list

What is slicing?

Selecting a range of elements from a list or string

What does list[start:end] return?

Elements from start up to but not including end

What does range(len(my_list)) allow you to do?

Loop through list indexes

What does % mean in Python?

Modulus (remainder)

What does index % 2 0 check?

If an index or number is even

What does index % 2 1 check?

If an index or number is odd

What is a for loop used for?

Repeating code for each item in a collection

How do you loop through values in a list?

for item in my_list

How do you loop through indexes in a list?

for i in range(len(my_list))

What is a nested loop?

A loop inside another loop

What is a 2D list?

A list containing other lists

How do you access an element in a 2D list?

my_list[row][column]

What does my_list[1][2] mean?

Row 2, column 3

What does my_list[1:3] do?

Returns rows 2 through 3, not including row 4

How can you create a 2D list?

By appending lists into another list

What is a list comprehension?

A shortcut for creating lists

Example of a list comprehension

[i · 2 for i in range(6)]

What is packing?

Storing multiple values in a collection such as a list or tuple

What is unpacking?

Assigning multiple variables from a collection

Example of unpacking

a, b, c = [1, 2, 3]

What is a string?

A sequence of characters

What does split() do?

Converts a string into a list

Example of split()

"Hello World".split() returns ["Hello", "World"]

What does join() do?

Converts a list into a string

Example of join()

" ".join(["Hello","World"]) returns "Hello World"

What does "a".join(["b","n","n"]) return?

banan

What is a dictionary?

A collection of key-value pairs

How do you access a dictionary value?

dictionary[key]

What does a dictionary map?

Keys to values

How do you loop through a dictionary?

for key in dictionary

What does compare?

Values

What does is compare?

Object identity (same object in memory)

If two lists contain the same values, what does return?

True

If two separate lists contain the same values, what does is usually return?

False

What file mode is used for reading?

'r'

What file mode is used for writing and overwriting?

'w'

What file mode is used for appending?

'a'

What file mode is used to create a new file only?

'x'

What does read() do?

Reads the entire file as a single string

What does read(size) do?

Reads a specific number of characters

What does readline() do?

Reads one line from a file

What does readlines() do?

Reads all lines and returns a list of strings

What does write() do?

Writes content to a file

What does write() return?

The number of characters written

What does seek() do?

Moves the file pointer to a specified position

What does seek(0) do?

Moves the file pointer to the beginning of the file

What does a positive seek offset do?

Moves the file pointer forward

What does close() do?

Closes an open file

Why should files be closed?

To save resources and ensure changes are written properly

What happens when a file is opened in 'w' mode?

Existing contents are overwritten

What happens when a file is opened in 'a' mode?

New content is added to the end

What does readlines() return?

A list where each element is a line from the file

What type of value does len() return?

Integer

What does print(my_list[3][1:]) do in a 2D list?

Prints elements from index 1 to the end of row 4

What is the output type of split()?

List

What is the output type of join()?

String

What is the difference between append() and extend()?

append adds one item; extend adds multiple items

Can tuples be modified after creation?

No

Can lists be modified after creation?

Yes

Can dictionaries be modified after creation?

Yes

What are the three most tested file-reading methods?

read(), readline(), readlines()

What are the three most common list methods?

append(), extend(), remove()

What are the most common list-processing functions?

len(), sort(), reverse()

What is the most important thing to remember about tuples?

They are immutable

What is the most important thing to remember about dictionaries?

They map keys to values

What is the most important thing to remember about 2D lists?

Use [row][column] indexing

What is the most important thing to remember about file mode 'w'?

It overwrites existing contents

What is the most important thing to remember about file mode 'a'?

It appends to the end without deleting existing content