Python tutorial (very detailed)

Python is a high-level programming language, which is easy to learn, highly readable and widely used. It is widely used in data analysis, artificial intelligence Web development, web crawler and other fields. This tutorial will lead the reader to learn Python from scratch, gradually master the basic syntax, data type, control flow, function definition, module import and other knowledge of Python, and lay a solid foundation for subsequent learning.

1、 Install Python

Before starting to learn Python, you need to install Python first. You can download the latest version of Python from the official Python website and install it according to your own operating system. During the installation process, it is recommended to check the "Add Python to PATH" option so that you can use the command line tool to run Python later.

2、 Write the first Python program

After installing Python, you can start writing the first Python program. Open the command line tool and enter the following code:

python

print("Hello, world! ")

This code uses the print function to output a string information. The print function is one of the most commonly used functions in Python, which is used to output the specified content to the screen.

3、 Data type

There are many data types in Python, including numbers, strings, Boolean values, lists, tuples, sets, dictionaries, etc. These data types and their basic usage are described below.

number

The number types in Python include integer (int), floating point (float), and complex. Integer type is used to represent integer, floating point type is used to represent numeric value with decimal part, and complex type is used to represent complex number. For example:

python

A=10 # integer

B=3.14 # floating point

C=2+3j # complex

character string

A string is a sequence of characters consisting of zero or more characters. In Python, you can use single quotation marks or double quotation marks to define strings. For example:

python

str1 = 'Hello, world!'

str2 = "Hello, Python! "

Boolean

Boolean values are two values in Boolean logic, usually represented by True and False. In Python, you can use if statements and conditional expressions to perform Boolean operations. For example:

python

a = True

b = False

C=a and b # Logical AND operation, the result is False

D=a or b # Logical OR operation, the result is true

4、 Control process

Control flow refers to the structure of condition judgment, cyclic execution, etc. in the program, which is used to control the execution sequence of the program. The control flow in Python includes conditional statements, loop statements, and exception handling.

Conditional statement

Conditional statements are used to execute different code blocks according to the conditions. Conditional statements in Python use if Elif and else keywords. For example:

python

a = 10

b = 20

if a < b:

print("a is less than b")

elif a == b:

print("a is equal to b")

else:

print("a is greater than b")

Loop statement

The loop statement is used to repeatedly execute the specified code block. Loop statements in Python include for loops and while loops. For example:

python

#For loop

for i in range(1, 6):

print(i)

#While loop

i = 1

while i < 6:

print(i)

i += 1

exception handling

Exception handling is used to catch exceptions in the program and handle them. Exception handling in Python uses try Except keyword. For example:

python

try:

#Code blocks that may throw exceptions

x = 1 / 0

except ZeroDivisionError:

#Code block for handling exceptions

print("Cannot divide by zero!")

These statements are relatively simple and introductory python statements. If you don't know what you want to know, you can refer to the introduction in this article. If you want to know more, you can check our website's introduction to these statements.