Week 1 - Introduction to Python

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Questions and Answers

What command is used in Windows Command Prompt to check the installed version of Python?

python --list

python version

python get-version

python --version (correct)

Which of the following is NOT a method to run Python code?

Executing in a web browser (correct)

Using a text editor and Windows Notepad

Running from the Command Line

Using an Integrated Development Environment (IDE)

Why is indentation critical in Python programming?

It makes the code look nice.

It is required to align code statements.

Indentation has no effect on the code.

Indentation indicates a block of code. (correct)

What is the correct way to create a single-line comment in Python?

<h1>This is a comment</h1> Signup and view all the answers

Which of the following statements about variables in Python is true?

Variables can hold multiple data types. Signup and view all the answers

When using triple quotes for multi-line comments, what is technically being used instead?

Multi-line strings Signup and view all the answers

What is the recommended number of spaces to use for indentation in Python?

4 spaces Signup and view all the answers

Which of the following environments is best suited for larger Python projects?

Integrated Development Environment (IDE) Signup and view all the answers

Which of the following is true about Python variable naming rules?

Variable names must begin with a letter or an underscore. Signup and view all the answers

What is the result of executing the statement print('Hello ' + 'World!')?

Hello World! Signup and view all the answers

Which function would be used to convert an integer to a string in Python?

str() Signup and view all the answers

Which of the following statements about variable types is correct?

Casting allows changing a variable's type after it has been created. Signup and view all the answers

In the expression print(5 + 10), what is the output?

15 Signup and view all the answers

Which output statement automatically adds spaces between variables?

print('Hello', 'World!') Signup and view all the answers

Which of the following is an example of a floating-point number?

-5.5 Signup and view all the answers

What will be the result of executing print('Age: ' + str(25))?

Age: 25 Signup and view all the answers

What is a defining characteristic of tuples in Python?

Tuples can include multiple data types Signup and view all the answers

How can you access the last item in a tuple?

By using index -1 Signup and view all the answers

Which operation can be used to join two tuples?

The + operator Signup and view all the answers

Which method can be used to retrieve all keys from a dictionary?

keys() Signup and view all the answers

What happens if you attempt to add an item to a dictionary with a key that already exists?

The new item replaces the existing item Signup and view all the answers

Which method would you use to remove an item from a dictionary by its key?

pop() Signup and view all the answers

Which statement is true about dictionaries in Python?

Dictionaries are changeable and maintain item order Signup and view all the answers

What happens if you try to access a key that does not exist in a dictionary?

It raises a KeyError Signup and view all the answers

What is the purpose of negative indexing in lists?

It enables accessing items from the end of the list. Signup and view all the answers

Which method is used to add an item to the end of a list?

append() Signup and view all the answers

How can you remove an item from a list if there are multiple occurrences of that item?

By using the remove() method, which only removes the first occurrence. Signup and view all the answers

What happens if you attempt to access an index that is out of range in a list?

An IndexError is raised. Signup and view all the answers

If you omit the start index when accessing a slice of a list, where does the slicing begin?

From the first item in the list. Signup and view all the answers

Which method or keyword can be used to check if a specific item exists in a list?

in Signup and view all the answers

What is the result of the clear() method when applied to a list?

It empties the list but retains the list object. Signup and view all the answers

How can you change the value of an item at a specified index in a list?

By directly assigning a new value to that index. Signup and view all the answers

What is the purpose of the 'else' keyword in exception handling?

To define a code block that runs if no errors are raised Signup and view all the answers

Which mode would you use with the open() function if you want to read data from a file without modifying it?

Read Mode (r) Signup and view all the answers

What is the result of opening a file in Write Mode (w)?

The file will be created if it doesn't exist or overwritten if it does. Signup and view all the answers

What will happen if you try to use Create Mode (x) on an existing file?

An error will be raised to prevent overwriting. Signup and view all the answers

What does the read() method of a file object do by default?

Returns the entire text content of the file. Signup and view all the answers

How can you specify the number of characters you want to read from a file?

By passing a parameter to the read() method Signup and view all the answers

What is the correct way to open a file in Python for both reading and writing, without truncating the file?

open('filename', 'a+') Signup and view all the answers

What keyword is used to intentionally raise an exception in Python?

raise Signup and view all the answers

Study Notes

Introduction to Python

Most PCs and Macs have Python pre-installed.
To check Python installation on Windows, use: python --version in Command Prompt.
Python can be downloaded for free from the official website if not installed.

Running Python Code

Command Line Execution: Save code in a .py file, navigate to its directory in command line, and execute using python filename.py.
Interactive Mode: Access the Python interpreter by typing python (or py). Execute code line by line.
Integrated Development Environment (IDE): Use IDEs like PyCharm, VS Code, or IDLE for writing and running Python code efficiently. IDLE is best for beginners and lightweight tasks.

Python Indentation

Indentation is essential in Python to define code blocks, unlike other languages where it is mainly for readability.
Common practice is to use four spaces for indentation.

Python Comments

Single-line comments start with #, ignored by the interpreter.
Multi-line comments can be created using multiple # or triple quotes (''' or """), but the latter is a multi-line string.

Python Variables

Variables are generic containers for data, without a fixed type.
Variable naming rules: must start with a letter/underscore, cannot start with a number, case-sensitive, and must not be a reserved keyword.
Examples of valid naming styles include camelCase, PascalCase, and snake_case.
Variables can be assigned multiple values in one line.
Use print() to output variable values, with + for string concatenation and , for automatic spacing.

Data Types

String (str): Sequence of characters enclosed in quotes (e.g., "Hello").
Integer (int): Whole numbers, both positive and negative (e.g., 5, -3).
Float (float): Numbers with decimal points (e.g., 3.14, -0.001).
Negative indexing allows slicing from the end of strings.

Python Lists

Lists store multiple items in a single variable, defined with square brackets.
List items can be mixed data types and can have duplicate values.
Access list items using indexing, with support for negative indexing.
Use in keyword to check for item presence and assign new values via indexing.
Methods: insert() to add at specific index, append() to add to the end, remove() to delete an item, and pop() to remove by index.

Python Tuples

Tuples are defined with round brackets and also store multiple items.
They are immutable, meaning items cannot be changed once set.
Tuples support indexing and negative indexing similar to lists.

Python Dictionaries

Dictionaries are defined with curly brackets and consist of key-value pairs.
Items are ordered and mutable (items can be changed, added, or removed).
Duplicate keys not allowed, but values can be duplicated.
Access items using keys and methods like get(), keys(), and values().

Python File Handling

Use open() function for file operations, accepting filename and mode parameters.
Modes:
- Read (r): Default mode for reading data; does not modify the file.
- Append (a): Adds new data to the end of the file.
- Write (w): Overwrites existing content with new data.
- Create (x): Creates a new file and throws an error if it already exists.
The read() method retrieves contents of a file, allowing you to specify character limits.

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Description

This quiz focuses on the basics of Python programming, specifically how to check for its installation and different methods to run Python code. It is ideal for beginners looking to familiarize themselves with Python's environment and execution methods.