Python Naming Conventions and Variable Handling

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Questions and Answers

What is the correct definition of Snake Case?

Each word is separated by an underscore character (correct)

Each word starts with a capital letter

Each word, except the first, starts with a capital letter

All letters are in uppercase

How can you assign the same value to multiple variables in Python?

variable1 = variable2 = value (correct)

value = variable1 + variable2

variable1 & variable2 = value

multiple(variable1, variable2) = value

What will happen if you try to unpack a collection of values into more variables than there are values?

It will ignore the extra variables

It will raise an error (correct)

It will assign None to the extra variables

It will assign default values to the extra variables

What is the preferred way to output multiple variables using the print() function?

Separate them with commas Signup and view all the answers

What characteristic defines a global variable in Python?

A variable defined outside of all functions Signup and view all the answers

Which of the following statements about the + operator in Python is correct?

It gives an error when combining a string and a number Signup and view all the answers

Which case style has all words starting with a capital letter?

Pascal Case Signup and view all the answers

If you want to print multiple variables belonging to different data types, which method should you avoid?

Concatenating them with + Signup and view all the answers

What happens to a global variable if a local variable with the same name is created inside a function?

The global variable remains unchanged. Signup and view all the answers

What keyword is used in Python to modify a global variable inside a function?

global Signup and view all the answers

Which statement correctly describes how to find the data type of an object in Python?

Use the type() function. Signup and view all the answers

When is the data type of a variable determined in Python?

When a value is assigned to the variable. Signup and view all the answers

What will bool(-3.1) evaluate to in Python?

True Signup and view all the answers

What happens if you attempt to use a variable declared as global without calling the function where it was declared?

The global variable remains unchanged. Signup and view all the answers

What is implied by the statement, 'non-zero values are considered True' in the context of Python's boolean values?

All non-zero floating-point numbers are evaluated to True. Signup and view all the answers

Which option provides a correct way to create a local variable while maintaining a global variable of the same name?

Simply assign a value to the variable within the function. Signup and view all the answers

What characteristic of lists ensures that the order of items remains consistent?

Ordered Signup and view all the answers

Which of the following is true about lists in Python?

Lists are indexed and can be accessed using their index number. Signup and view all the answers

How can you find out the number of elements in a list?

Use the len() function. Signup and view all the answers

When using negative indexing in a list, what does the index -1 represent?

The last item in the list. Signup and view all the answers

What do lists in Python allow that makes them different from sets?

The allowance of duplicate values. Signup and view all the answers

Which of the following is a valid way to create a list in Python?

Using square brackets: []. Signup and view all the answers

How would you check if an item exists in a list?

Use the 'in' keyword. Signup and view all the answers

What does it mean for a list to be 'changeable'?

The items can be added, removed, or changed. Signup and view all the answers

What does the remove() method do when called on a list?

Removes the first occurrence of a specified item Signup and view all the answers

What happens if you call the pop() method without an index argument?

Removes the last item from the list Signup and view all the answers

Which keyword can be used to remove a specific index or the entire list in Python?

del Signup and view all the answers

Which method would you use to empty a list while keeping the list itself intact?

clear() Signup and view all the answers

How can you loop through a list using index numbers?

By using the len() function and range() Signup and view all the answers

What should you remember to do when using a while loop to iterate through a list?

Increase the index by 1 after each iteration Signup and view all the answers

What is the effect of multiple calls to the remove() method with the same value in a list?

No change occurs after the first removal Signup and view all the answers

Which method allows you to delete an item from a list while also specifying its index?

pop() Signup and view all the answers

Which method allows you to concatenate lists in Python by adding each item from one list to another individually?

append() method Signup and view all the answers

What character is used to denote tuples in Python?

Round brackets () Signup and view all the answers

Which of the following statements is true about Python tuples?

Tuples maintain the order of items. Signup and view all the answers

What is the difference between lists and tuples in Python?

Lists are ordered and changeable, while tuples are ordered and unchangeable. Signup and view all the answers

Which data type in Python is NOT one of the built-in collection types?

Array Signup and view all the answers

What will the len() function return when used on a tuple?

The number of items in the tuple. Signup and view all the answers

Which collection type is unordered and does not allow duplicate values?

Set Signup and view all the answers

What method can be used to combine two lists without altering the first one?

The + operator Signup and view all the answers

Study Notes

Naming Conventions

Camel Case: Every word except the first starts with a capital letter, like userName
Pascal Case: Every word starts with a capital letter, like UserName
Snake Case: Each word is separated by an underscore, like user_name

Assigning Values to Multiple Variables

You can assign values to multiple variables in a single line, ensuring the number of variables matches the number of values.

Unpacking Collections

Python lets you extract values from a list, tuple, etc., into variables. This is called unpacking.
For example, fruit = ["apple", "banana", "cherry"], x, y, z = fruit will assign apple to x, banana to y, and cherry to z.

Outputting Variables

The print() function is used to display values, including variables.
Use commas to separate multiple variables in the print() function.
You can also use the + operator to combine strings and variables in print(), but be mindful of spaces and data types.
Avoid using + with strings and numbers to prevent errors.

Global Variables

Variables created outside functions are called global variables and can be accessed anywhere.
Variables defined inside functions are local and only accessible within that function.
If you use the same variable name inside and outside a function, the function will work with a local variable, leaving the global variable unchanged.
The global keyword declares a variable inside a function as a global variable, allowing modification of the global variable.

Data Types

Python uses built-in data types to store different kinds of data.
Use the type() function to determine the data type of an object.
The data type is automatically assigned when you give a variable a value.
You can explicitly specify data types using constructor functions: int(), float(), str(), and bool().

Lists

Store multiple items in a single variable, using square brackets [].
Ordered, changeable, and allow duplicate values.
Items are indexed, starting from 0 for the first item.
Use the len() function to find the number of items.
Items can be of any data type.
You can use the list() constructor to create a list.
Use the type() function to determine the data type of each element in a list (for mixed data types).

Accessing List Items

Access items using their index number.
Use a colon : to specify a range of indexes.
Negative indexes start from the end of the list (-1 for the last item).
Use the in keyword to check if an item exists in a list.

Removing List Items

remove() method removes the first occurrence of a specified item.
pop() method removes the item at a specified index, or the last item if no index is given.
del keyword removes items at a specified index or removes the entire list.
clear() empties the list, but the list object still remains.

Looping through Lists

Use a for loop to iterate over each item in a list.
Use a while loop with the len() function and index to iterate through list items.

Joining Lists

Use the + operator to concatenate lists.
Use the append() method to add items from one list to another one by one.
Use the extend() method to add all items from one list to another list.

List Methods

append(): Adds an element to the end of the list.
insert(): Inserts an element at a specific index.
remove(): Removes the first occurrence of a specified element.
pop(): Removes the element at a specified index, or the last element if no index is given.
clear(): Removes all elements from the list.
index(): Returns the index of the first occurrence of a specified element.
count(): Returns the number of occurrences of a specified element.
sort(): Sorts the list in ascending order.
reverse(): Reverses the order of the elements in the list.
copy(): Returns a copy of the list.

Tuples

Store multiple items in a single variable, using parentheses ().
Ordered and unchangeable (cannot be modified after creation).
Items are indexed, starting from 0 for the first item.
Allow duplicate values.
Use the len() function to find the number of items.
Items can be of any data type.
You can use the tuple() constructor to create a tuple.

Python Collections

Lists: ordered, changeable, allow duplicates.
Tuples: ordered, unchangeable, allow duplicates.
Sets: unordered, unchangeable, unindexed, do not allow duplicates.
Dictionaries: ordered, changeable, do not allow duplicate keys.

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Description

Test your knowledge on Python naming conventions, variable assignments, and unpacking collections. This quiz covers essential practices in Python programming that every developer should know. Identify the correct methods and syntax to effectively manage variables in your code.