>>> 1 if 5>3 else 0
1
>>> 1 if 5<3 else 0
0

import copy
# ######### 数字、字符串 #########
n1 = 123
# n1 = "i am alex age 10"
print(id(n1))
# ## 赋值 ##
n2 = n1
print(id(n2))
# ## 浅拷贝 ##
n2 = copy.copy(n1)
print(id(n2))
22219144
# ## 深拷贝 ##
n3 = copy.deepcopy(n1)
print(id(n3))
22219144

n1 = {"k1": "wu", "k2": 123, "k3": ["alex", 456]}
n2 = n1

import copyn1 = {"k1": "wu", "k2": 123, "k3": ["alex", 456]}n3 = copy.copy(n1)

import copyn1 = {"k1": "wu", "k2": 123, "k3": ["alex", 456]}n4 = copy.deepcopy(n1)

def emil(p):import smtplibfrom email.mime.text import MIMETextfrom email.utils import formataddrmsg = MIMEText('邮件内容', 'plain', 'utf-8')　　# From 后面的邮箱地址一定要跟发送邮箱地址相同，不然会认证失败msg['From'] = formataddr(["武沛齐",'wptawy@126.com'])msg['To'] = formataddr(["走人",'424662508@qq.com'])msg['Subject'] = "主题"server = smtplib.SMTP("smtp.126.com", 25)server.login("wptawy@126.com", "邮箱密码")server.sendmail('wptawy@126.com', [p,], msg.as_string())server.quitemail("244591052@qq.com")

import hashlib
# 设置自己的加密字符串，防止他人撞库破解
hash = hashlib.md5(bytes('sfa',encoding='utf-8'))
# 设置加密的密码
hash.update(bytes('123',encoding="utf-8"))
print(hash.hexdigest())
# b72a6beb24eef36c247274014dd4ade3

import hashlibdef md5(arg):hash = hashlib.md5(bytes('licheng', encoding='utf-8'))# 设置加密的密码hash.update(bytes(arg, encoding="utf-8"))return hash.hexdigest()def register(user,pwd):with open("db",'a',encoding="utf-8") as f:temp = user + "|" + md5(pwd)+ "\n"f.write(temp)def login(user,pwd):with open("db","r",encoding="utf-8") as f:for line in f:u, p = line.strip().split("|")if u == user and p == md5(pwd):return Truechoose = input("1.登录\n 2.注册")
if choose == "2":user = input("用户名：")pwd = input("密码：")register(user,pwd)
elif choose == "1":user = input("用户名：")pwd = input("密码：")judge = login(user,pwd)if judge:print("登陆成功")else:print("登录失败")

实例：登录密码加密保存

>>> for i,j in enumerate([1,2,3]):print i,j0 1
1 2
2 3
>>> for i,j in enumerate({'a':1,'b':2}):print i,j#字典默认遍历key
0 a
1 b

li = ['冰箱','彩电','洗衣机']
# 可以指定序号从什么开始计数
for index,i in enumerate(li,1):print(index,i)
# 1 冰箱
# 2 彩电
# 3 洗衣机
# 虽然显示是从1开始，但系统内还是以0开始计数的

>>> range(1,5) #代表从1到5(不包含5)
[1, 2, 3, 4]
>>> range(1,5,2) #代表从1到5，间隔2(不包含5)
[1, 3]
>>> range(5) #代表从0到5(不包含5)
[0, 1, 2, 3, 4]

print(__name__)  #本文件被执行时输出__main__,否则输出模块名print(__doc__)  #输出 py 文件的注释print(__file__)   # 输出自己文件的路径
#可以配合常用os操作完成系统路径的修改：
p1 = os.path.dirname(__file__)
p2 = "lib"
my_dir = os.path.join(p1, p2)
sys.path.append(my_dir)print(__package__)  # 输出当前.py所在文件夹，用.划分