Python FAQ
- Introduction
- Variables in Python
- Programming
- Instructions
- Modules
- Script Examples
Introduction to Python
- What is Python?
- What are the advantages of Python?
- Which operating system should I use for Python?
- Who created Python?
- Why is it called Python?
- What does "interpreted language" mean?
- What does "interactive language" mean?
- What does "object-oriented language" mean?
- How do I install Python on a Windows PC?
- How do I install Python on Linux?
- Are there online Python emulators?
- How to stop a running program
- How to start debugging a program
- What are exceptions in Python?
- What are Python operators?
- What is indentation?
- How to add comments in code
- How to create a loop
- What is introspection?
- How to define a function
- How to use classes in Python
- How to use decorators
- How to do profiling
- How to create an iterator
- How to create a generator
What is Python?
Python is an interpreted, interactive, and object-oriented programming language.
What are the advantages of Python?
Unlike other programming languages, Python has a simple and intuitive syntax. It also incorporates many positive aspects from other languages.
Which operating system should I use for Python?
Python is a portable language. It can run on Windows, Linux, Unix, Mac, and more. You just need to install the Python interpreter on your operating system.
Note: If you know the C language, you can also customize the Python interpreter software to suit your programming needs and create your own custom release.
Who created Python?
Python was created in 1989 by Dutch developer Guido Van Rossum. He released it for free on Usenet in 1991.
Why is it called Python?
The language is named after Monty Python, as Van Rossum was a fan of the British comedy group's sketches.
What does "interpreted language" mean?
It means that the source code of a Python program is executed by another software called an interpreter. Unlike C, Python programs do not need to be compiled.
What does "interactive language" mean?
It means that Python instructions can be executed directly from the command prompt without creating a source code file.
What does "object-oriented language" mean?
It means that Python allows the creation of objects with properties, classes, and attributes. This is known as object-oriented (OO) programming.
How do I install Python on a Windows PC?
The Python interpreter can be freely installed on Windows PCs. It can be downloaded and installed for free.
How do I install Python on Linux?
Python is usually pre-installed in Linux distributions. Just go to the command line and type python or python3.
Are there online Python emulators?
Yes, there are several free online platforms that allow you to program in Python. They are useful for getting familiar with the language without installing anything on your PC.
How to stop a running program
To stop a running Python program in the shell, simply press CTRL+C on the command line.
How to start debugging a program
To debug a program, you use a special module called pdb (Python debugger). This module pauses program execution and opens a prompt where you can set various debug commands.
import pdb
pdb.set_trace()
Programming in Python
What are exceptions in Python?
During program execution, unexpected events (e.g., entering a number instead of a name) may occur. Exceptions allow programmers to handle these unexpected events, correct them, and prevent the program from returning an error. In Python, you can manage both expected (handled) and unexpected (unhandled) events.
Note: Van Rossum likely incorporated positive aspects from other programming languages when creating Python. In this case, he was inspired by Java's exception handling.
What are Python operators?
Python uses logical, mathematical, boolean, and comparison operators similar to those in other programming languages. However, there are significant differences. For example, exponentiation is calculated using ** instead of ^.
What is indentation?
In Python's conditional structures, a block of instructions is defined using significant indentation. Each instruction is preceded by a certain number of spaces (zero or more), which changes its position in the lines of code. The position of the instruction within the structure affects the program's execution. Unlike C, Python does not use braces or keywords (then, end-if, etc.).
- if age<18:
print('Access denied')- access = False
- else:
- print('Access granted')
- access = True
How to add comments in code
To comment on the source code in Python, use the # (hash) symbol. Commented lines are not executed by the interpreter.
# this is a comment
How to create a loop
To create an iterative structure in Python, use the while and for statements.
The while statement allows you to create both conditional and unconditional loops.
While [condition]:
block of instructions
The for statement is used only for unconditional loops.
for [object]:
block of instructions
For more information on iterative structures in Python, click here.
What is introspection?
It is a feature of Python that allows you to inspect the attributes of an object from outside. For example, you can view the functions in a module or the attributes of a class.
How to define a function
To define a function in Python, use the def() statement.
def average(a,b):
c = (a + b) / 2
return c
How to use classes in Python
Python allows the creation of classes and object-oriented programming.
class Name():
....
How to use decorators
Decorators are functions that take another function as input.
How to do profiling
Profiling is a tool that checks the number of times individual lines of a script are executed and their corresponding execution times. It can also be performed on a single function.
import cProfile
cProfile.run('function_name()')
How to create an iterator
An iterator is an object or class that returns the elements of an iterable one at a time. You define the list with the iter() function and read it with the next() function.
list = [1, 2, 3]
list2 = iter(list)
next(list2)
How to create a generator
Generators are functions that return one element of an iterable at a time. They are similar to functions.
def generator():
yield x
object = generator()
next.object()
Useful Python Scripts
A list of useful scripts, examples, and practical solutions.
- How to write program code on multiple lines
- How to open a URL with Python
- How to create a graph
- How to run a Python script (.py) online with PHP
- How to measure the execution time of a statement
- How to pass a variable from PHP to Python
- How to generate random numbers in Python
- How to create a display mask
- How to convert a string to a list/tuple
- How to create a function library (module)
- How to program with multithreading in Python
Some useful functions for mathematical calculations:
- How to calculate the square root
- How to normalize a vector
- How to calculate a function's limit
- How to calculate the first, second, or third derivative
- How to plot a mathematical function in Python
- How to plot a derived function graph
- How to calculate the indefinite integral
- How to calculate the definite integral
- Solving a differential equation
- Calculating linear or polynomial regression
- Calculating chi-square
- Creating a chi-square table
Here are some handy scripts for working with media files:
