Introduction to Python Programming

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Questions and Answers

Explain the difference between a list and a tuple in Python. Why might you choose one over the other?

Lists are mutable, ordered collections defined with square brackets [], while tuples are immutable, ordered collections defined with parentheses (). Tuples are more memory efficient and can be used as keys in dictionaries due to their immutability, whereas lists are preferred when the collection needs to be modified.

Describe the purpose of virtual environments in Python development and how they can be created and activated.

Virtual environments isolate project dependencies to avoid conflicts. They are created using venv via python3 -m venv myenv (for example) and activated using a script within the environment's directory, such as source myenv/bin/activate on Unix-like systems.

How does Python's dynamic typing differ from static typing, and what are the advantages and disadvantages of dynamic typing?

In dynamic typing, variable types are checked during runtime, whereas in static typing, types are checked before runtime. Dynamic typing allows for faster development and more flexible code but can lead to runtime errors that might be caught earlier with static typing.

Explain the use of `try` and `except` blocks in Python. Provide a scenario where using these blocks would be crucial.

<code>try</code> and <code>except</code> blocks are used for error handling. The <code>try</code> block contains code that might raise an exception, and the <code>except</code> block specifies how to handle the exception if it occurs. A crucial scenario would be handling file input/output operations, where a <code>FileNotFoundError</code> might occur if the specified file does not exist. Signup and view all the answers

Describe briefly how to define a class in Python that inherits from a parent class and overrides one of the parent's methods.

To define a class that inherits from a parent, specify the parent class in the class definition (e.g., <code>class ChildClass(ParentClass):</code>). To override a method, define a method with the same name in the child class. For example: <pre><code class="language-python">class Parent: def method(self): print('Parent method') class Child(Parent): def method(self): print('Child method') </code></pre> Signup and view all the answers

Explain the purpose and usage of list comprehensions in Python. Provide a short example.

List comprehensions offer a concise way to create lists based on iterables. They consist of an expression followed by a <code>for</code> clause and optional <code>if</code> clauses. For Example: <pre><code class="language-python">squares = [x**2 for x in range(10) if x % 2 == 0] </code></pre> This creates a list of squares of even numbers from 0 to 9. Signup and view all the answers

What are lambda functions in Python, and when might you choose to use them instead of regular functions?

Lambda functions are anonymous, single-expression functions defined using the <code>lambda</code> keyword. They are typically used for short, simple operations where a full function definition is unnecessary, such as in <code>map()</code>, <code>filter()</code>, or <code>sorted()</code> functions. For example: <pre><code class="language-python">squared = map(lambda x: x**2, [1, 2, 3]) </code></pre> Signup and view all the answers

Explain the concept of decorators in Python and provide a simple example showing how to define and use one.

Decorators are functions that modify the behavior of other functions. They use the <code>@</code> syntax to wrap a function, adding functionality before or after its execution. For Example: <pre><code class="language-python">def my_decorator(func): def wrapper(): print("Before function") func() print("After function") return wrapper @my_decorator def say_hello(): print("Hello!") say_hello() </code></pre> Signup and view all the answers

What are Python generators, and how do they differ from regular functions in terms of memory usage and execution?

Generators are functions that produce a sequence of values using the <code>yield</code> keyword. Unlike regular functions that return a value and terminate, generators maintain their state between calls and generate values on demand, saving memory compared to creating and storing an entire list at once. Generators are useful for large sequences. For example: <pre><code class="language-python">def generate_numbers(n): for i in range(n): yield i numbers = generate_numbers(10) print(next(numbers)) </code></pre> Signup and view all the answers

Briefly describe the purpose of the Pandas library in Python, and give an example of a common operation performed using Pandas.

Pandas is a library for data manipulation and analysis, providing data structures like DataFrames for efficient storage and manipulation of tabular data. A common operation is reading a CSV file into a DataFrame: <code>import pandas as pd; df = pd.read_csv('data.csv')</code>. Signup and view all the answers

Flashcards

What is Python?

A high-level, general-purpose language that emphasizes code readability through significant indentation.

Variable Declaration

Variables in Python are declared by simply assigning a value to them.