Python

Question 1

How to run a python file?

Answer 1

Navigate to file location in terminal. run “python file.py”

Question 2

What’s a variable in Python?

Answer 2

Variables are labels. They reference a value.

Question 3

What are the rules for naming variables in Python?

Answer 3

• They can only contain letters, numbers, and underscore
• They can start with a letter or an underscore, but not a number
• Spaces are not allowed in variables
• Avoid using Python keywords such as print or class
• Variables should be short and descriptive

Question 4

What’s a string in Python?

Answer 4

In programming, programs collect data and do something with them. Since they are different types of data, it helps to differentiate the different types.

A string is a data type. A string is a series of characters. Anything inside a single or double quote is a string.

Examples of string:

• “this is a string”
• ‘this is a string’

Question 5

What is the string method title do in Python?

Answer 5

It capitalizes each first letter of a string

```python
name = “james leveille”
print(name.title())
~~~

Question 6

What is the string method upper do in Python?

Answer 6

upper case a string
name.upper()

Question 7

What is the string method lower do in Python?

Answer 7

It lower case a string
name.lower()

Question 8

How to use variables in a string in Python?

Answer 8

By using the f keyword to format the string.

print(f”{fName} {lName}”)

Question 9

How to add a tab in a string in Python?

Answer 9

\t
print(“\tname”)

Question 10

How to add a new line in a string in Python?

Answer 10

\n
print(“\nname”)

Question 11

How to remove write space from a string in Python?

Answer 11

name = “ James “
// remove left whitespace
name.lstrip()
// remove right whitespace
name.rstrip()
// remove left and right whitespace
name.string()

Question 12

How to remove a part of string from a string in Python?

Answer 12

remove prefix

name = “James”
name.removeprefix(“Ja”)
# remove suffix
name.removesufix(“es”)

Question 13

What’s a list in Python?

Answer 13

A list is a way of storing a list of items. Square brackets ([]) are used to create a list. Lists in python are zero index-based. You can access them by passing an index.

bicycles = ['trek', 'cannondal', 'redline', 'spcialized']

Question 14

How do you access an element of a list in Python?

Answer 14

bicycles[0]

Question 15

How do you access the last element of a list?

Answer 15

you can use Python special syntax bicycles[-1]. If you pass -1, python will return the last element in the list. -2 return the second item from the end and so forth

Question 16

How do you modify an element in the list in Python?

Answer 16

Just set the data using the indexbicycles[0] = “LUKI”

Question 17

How do you add an element to a list in Python?

Answer 17

• You can append the element to the end of the list. bicycles.append('ducati')
• You can also insert the element at a certain position bicycles.insert(0, 'ducati') This will insert the new element and shift the rest of the list

Question 18

How do you remove an item from a list in Python?

Answer 18

• You can use del to delete an element given its index. For example, del bicycles[0] will delete the first element of the list. If the index is not found, it will throw an out of index error
• pop is another way you can remove an item from the list. Pop removes the last element of the list and returns the value.
  popped_item = bicycles.pop()

Question 19

How do you remove an item from the list given the value in Python?

Answer 19

You remove an item if you know the value by calling the remove method on the list. bicycles.remove(‘ducati’). This will remove the first occurrence of that value.

Question 20

How to sort a list in Python?

Answer 20

• sort - this will sort the list permanently.
  bicylces.sort()
• sorted - sorted is a function that you can call on your list to sort it.
  newList = sorted(bicycles)

Question 21

How do you loop through a list in Python?

Answer 21

bicylces = ["ice", "looki", "pit", "brake"]

```python
for bike in bicycles:
print(bike)
~~~

The colon (:) is required.

The line after the : must be indented

Question 22

How do you loop through a list of numbers in Python?

Answer 22

range (k, n) - is use to iterate over a list start at k through n-1

range (n) - is use to iterate over a list start at 0 through n-1

```python
for value in range(1, 5):
print(value)
~~~

Question 23

How do you access the last item of a list?

Answer 23

players = [“john”, “luke”, “peter”]. print(players[-1]will print peter

Question 24

How do you convert a range to a list?

Answer 24

list = list(range(0, 4)). This will return [0, 1, 2, 3] because list converts a range to a list.

Question 25

How do you generate a subset of a list using range in Python?

Answer 25

```python players = ['charles', 'martina', 'michael', 'florence', 'eli'] print(players[0:3]) # or print(players[:3] # start from the beginning of the list ```

Question 26

How do you copy a list from another list in Python?

Answer 26

```python players = ['charles', 'martina', 'michael', 'florence', 'eli'] copied_players = players[:] ```

Question 27

What is a Tuple in Python and why use it?

Answer 27

A tuple allows you to create a list that is immutable (can not change). Here is how you define a tuple `dimensions = (200, 50)` Here is how you access it. `print(dimensions[0])` If you were trying to change this value, Python will throw an error `dimensionsp[0] = 123`. This will throw an error.

Question 28

How do you create an if statement in Python?

Answer 28

if car == "bmw" : print(car.upper()) if car == "audi" and age >= 21: print("able to rent")

Question 29

How do you create an else if block in Python?

Answer 29

if age > 18 : print("can vote") elif age > 21: print("can vote and drink") else: print("too young")

Question 30

What’s a dictionary in Python?

Answer 30

A dictionary in Python is a collection of key-value pairs. Each key is connected to a value, and you can use a key to access the value associated with that key. A key’s value can be a number, a string, a list, or even another dictionary. In fact, you can use any object that you can create in Python as a value in a dictionary. `alien_0 = {'color': 'green', 'points': 5` - You can add or remove a key from a dictionary

Question 31

How to access the value of a key of a dictionary?

Answer 31

Give the name of the dictionary and the place the key inside a set of square brackets `alien_0['points']` Another way to retrieve is to use the get method. It’s better to use because if the key doesn’t exist, it won’t throw an error, it will return none. `alien_0.get('points')` will return `5` `alien_0.get('badkey')` will return `none`

Question 32

How to loop through a dictionary?

Answer 32

- How to loop through a dictionary? you can loop through all the key, pair ```python for key, value in user_0.items(): print(f"\nKey: {key}") print(f"Value: {value}") ``` or all the keys ```python for name in favorite_languages.keys(): print(name.title()) ``` or all the values ```python for language in set(favorite_languages.values()): print(language.title()) ```

Question 33

How do you get data from the user in Python?

Answer 33

You can use the `input()` function to get data from the user - The input function pauses the program and waits to get the user to enter text - `message = input("Enter a word")` - this creates a variable named message and assigns the value of the user’s input to this variable

Question 34

How do you convert a string to an integer in Python?

Answer 34

numb = int('23')

Question 35

What does the module % do in Python?

Answer 35

The modulo operator tells you what the remainder is when you divide a number by a number. 6 % 2 is 0. This means the remainder of 6 / 2 is zero.

Question 36

What’s a while loop in Python and what’s the syntax?

Answer 36

The while loop runs as long as a certain condition is true. If the condition is always true, the loop will run forever. So make sure to have the condition false so that the loop may stop ```python current_number = 1 while current_number <= 5: print(current_number) current_number += 1 ```

Question 37

How do you define a function in Python?

Answer 37

To define a function use the keyword `def`, then the name of the function, followed by `()` . The parentheses are required and inside of them you pass the information that are required to run the function. If you pass nothing, then nothing is required to run the function. ```python def greet_user(): print("hello") ``` To call the function use `greet_user()`

Question 38

What is a parameter and argument in Python?

Answer 38

In Python, when you define a function, you can specify **parameters**, which act as placeholders for values the function will receive. **Example of a Parameter:** ```python python def greet_user(username): print(f"Hello, {username}!") ``` In this function, `username` is a **parameter**—it defines the expected input when the function is called. --- When you call the function and provide a value, that value is called an **argument**. **Example of an Argument:** ```python python name = "Louis" greet_user(name) ``` Here, `name` (which holds the value `"Louis"`) is the **argument** being passed to the `greet_user` function. **Key Difference:** - **Parameter** → A variable inside the function definition (e.g., `username`). - **Argument** → The actual value passed when calling the function (e.g., `"Louis"`).

Question 39

How do you create a function that returns a value in Python?

Answer 39

You just need to have the keyword return in the function

Question 40

How do you pass a number of arguments in a function in Python?

Answer 40

To pass a series of arguments, you use `*parameter_name` when defining the function. This allows the function to accept multiple arguments as a **tuple**. If you have multiple parameters, it's important to place the parameter with `*` (which collects multiple arguments) **at the end** of the parameter list. **Example:** ```python python CopyEdit def greet_names(*names): for name in names: print(f"Hello, {name}!") ``` Here, `*names` allows the function to accept multiple names as arguments. **Example with Multiple Parameters:** ```python python CopyEdit def greet(group, *names): print(f"Greetings to the {group} group!") for name in names: print(f"Hello, {name}!") ``` In this case, `group` is a regular parameter, while `*names` collects multiple additional arguments.

Question 41

What are modules in Python? What are their advantages? How to use them?

Answer 41

- **Modules in Python** are separate files that contain different functions. - Using modules is important because they help **reuse code** and **encapsulate low-level details**, making programs more organized and maintainable. - To import all functions from a module, use: ```python python CopyEdit import pizza ``` - To import a specific function from a module, use: ```python python CopyEdit from pizza import make_pizza ``` - You can also use an **alias** when importing modules and functions for better readability or convenience. **Example:** ```python python CopyEdit import pizza as p from pizza import make_pizza as mp ```

Question 42

Tips on style when creating a function

Answer 42

- Functions should have descriptive names, and these names should use lowercase letters and underscores. Descriptive names help you and others understand what your code is trying to do. Module names should use these conventions as well. - Every function should have a comment that explains concisely what the function does. This comment should appear immediately after the function definition and use the docstring format. - If you specify a default value for a parameter, no spaces should be used on either side of the equal sign: