环境安装

# macos 一键安装
brew install python@3.12.5

# windows 手动下载 & 安装
# https://www.python.org/downloads/

快速体验

1. 新建文件(以 .py 为文件后缀) touch hello.py
2. 输入代码

print("hello world")

3. 执行: python ./hello.py

注释

注释就是: 写在代码中, 但是会被编译器忽略, 并不会执行的内容

print("我不是注释可以执行")

# 单行注释

'''
多行注释1
'''

"""
多行注释2
"""

print("我不是注释可以执行")

变量 & 命名规范

1. 不能以数字开头, 不能以 \$ 开头, 可以 \_ 开头
2. 不能包含特殊字符, 如 #@% 等
3. 变量名不能是保留字
4. 大小写敏感

name="tom"
_age=10;

# 如以下变量名是无法通过编译的
# $gender='male' # x
# 3a=1;       # x
# if=1        # x

关键字(保留字)

查看保留字

import keyword

print(keyword.kwlist)

# python 所有关键字
# [
#   "False",
#   "None",
#   "True",
#   "and",
#   "as",
#   "assert",
#   "async",
#   "await",
#   "break",
#   "class",
#   "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"
# ]