Python syntax analysis: demystifying programming

python Basic structure of syntax

Python The syntax is known for its simplicity and readability. Code blocks end with a colon (:), and the indentation indicates the nesting level of the code block. There is no explicit semicolon (;) in Python, instead newline characters are used to separate statements.

# 这是一个单行注释
"""
这是一个多行注释
"""

print("Hello, world!")# 输出文本

Keywords and Identifiers

Python has some reserved keywords that have special meanings and cannot be used as variable names. Here are some common keywords:

and, as, assert, break, continue, def, del, elif, else, except,
finally, for, from, global, if, import, in, is, lambda, nonlocal,
not, or, pass, raise, return, try, while, with, yield

The variable name is an identifier used to store the value. They consist of letters, numbers, and underscores, but cannot begin with a number. Variable names should be descriptive so that the intent of the program can be understood.

type of data

Python supports multiple data types, including:

• Integer type (int): Integer, such as 1, -50
• Float type (float): Floating point number, such as 3.14, -1.618
• String (str): Text sequence, such as "Hello", "World"
• Boolean type (bool): Boolean value, only True or False
• List: Ordered and variable value Set, such as [1, 2, 3], ["apple", "banana", "cherry" ]
• Tuple (tuple): An ordered and immutable collection of values, such as (1, 2, 3), ("apple", "banana", "cherry")
• Dictionary (dict): A collection of key-value pairs, where the keys are unique and immutable, such as {"name": "John", "age": 30}
• Set (set): An unordered and unique set of values, such as {1, 2, 3}

Variable assignment

Variable assignment is done using the equal sign (=) operator. For example:

# 声明一个整数变量
age = 30

# 声明一个字符串变量
name = "John Doe"

# 声明一个列表变量
fruits = ["apple", "banana", "cherry"]

Process Control

Python’s flow control statements are used to control the order of program execution. Common flow control statements include:

• if-else statement: Execute different code blocks based on conditions.
• for loop: Traverse each element in the sequence.
• while loop: Repeat the execution of the code block as long as the condition is true.
• break and continue statements: used to terminate or skip loops early.

function

A function is a modular unit that encapsulates a block of code. They can receive parameters, perform operations and return results. In Python, functions are defined using the def keyword:

def greet(name):# 定义一个名为 greet 的函数
print(f"Hello, {name}!")# 在函数中打印文本

# 调用 greet 函数
greet("John")

Object-Oriented Programming Python supports object-oriented programming (OOP). OOP allows you to create classes to represent objects, which have data and methods. Classes can be defined using the class keyword:

class Person:# 定义一个名为 Person 的类
def __init__(self, name, age):# 构造函数
self.name = name# 为对象创建属性
self.age = age

def get_name(self):# 定义一个方法
return self.name

# 创建 Person 对象
person = Person("John", 30)

# 访问对象属性
print(person.name)

# 调用对象方法
print(person.get_name())

Summarize

Python's syntax is simple and clear, with powerful functions and flexibility. You can easily build a variety of applications with Python by mastering its basic structure, data types, flow control, and object-oriented programming concepts. From simple scripts to complex systems, Python is a powerful

programming language

that can meet a variety of development needs.

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