Python 基础字符串拼接 + if while for循环 - Python

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Python 基础字符串拼接 + if while for循环(二)

2017-09-30 17:19:09 【大中小】浏览:2988次

x:{2}'''.format(name, age, sex)

模块定义：
密文密码：getpass 引用后使用，getpass.getpass()
if else 使用
例：

username = "username"
password = "123456"
_Username = input("Username:")
_Passwd = input("Password:")
if username == _Username and password == _Passwd:
    print("welcome user {name} to beij".format(name=username))
else:
    print("Invalid  username or passwd")

if elif else
例：

Myage = 37
InputAge = int(input("please input my age:"))
if InputAge == Myage:
    print("It's right")
elif InputAge > Myage:
    print("Think small")
else:
    print("Think big")

While else 循环
count = 0
while count < 3:
    Myage = 37
    InputAge = int(input("please input my age:"))
    if InputAge == Myage:
        print("It's right")
        break
    elif InputAge > Myage:
        print("Think small")
    else:
        print("Think big")
    count+=1
else:
    print("fuck you!")

break 跳出当前整个循环
continue 跳出当前循环，进入下次循环

作业

编写登陆接口

输入用户名密码
认证成功后显示欢迎信息
输错三次后锁定

old_uname = open(r'C:\Users\Administrator\Desktop\username.txt', 'r').readlines()
count = 0
while count < 3:
    username = input("please your username:")
    passwd = input("please your passwd:")
    for i in old_uname:
        if i == username:
            print("wolcome to your blogs:{_uname}".format(_uneme=username))
            break
        else:
            continue
    else:
        count += 1
        if count == 3:
            continue
        print("The password you entered is incorrect!please input again...")
else:
    print("三次错误，账号已锁定")
    open(r'C:\Users\Administrator\Desktop\lockname.txt', 'a').write(username + '\n')

字符串基础

#字符串操作
#去掉空格 strip () 括号内可指定 默认是空格

username = input("username:")
if username.strip('-') == "zhang":
    print(username.strip('-'))
    print("welcome %s to beijing" % username)

# 分割 split 可指定根据什么分割

list11 = "welcome to beijing"
list2 = list11.split()
print(list2)  # ['welcome', 'to', 'beijing']

# 合并 join 可指定根据什么合并

list3 = ":".join(list2) + '\n'  # welcome:to:beijing
list4 = " ".join(list2)  # welcome to beijing
print(list3, list4)

# 判断有没有空格\切片

name = "mr,niu"
print("," in name)
name1 = "mr niu"
print(" " in name1)
print(name[2:4])

# format 字符串格式化

men = "my name is {name}, age is {age}"
all = men.format(name="niu", age=23)

men1 = "my name is {0}, age is {1}"
all1 = men1.format("niu", 23)
print(all1)

fill = "niu"
fill.isdigit()  # 判断是不是数字
fill.endswith('')  # 判断是不是以指定字符串结尾
fill.startswith('')  # 判断是不是以指定字符串开头

fill.upper()   # 批量转换成大写 fill.lower() # 批量转换成小写 fill.capitalize() # 第一个字母大写，其他都小写 fill.title() # 每个单词的首字母大写，其他都小写

print(fill.center(20, '='))


（1）、转义字符串             
（2）、raw字符串--转义机制  open(r'c:\tmp\a.txt','a+')
（3）、Unicode字符串
（4）、格式化字符串  "age %d,sex %s,record %m.nf"%(20,"man",73.45)
字符串基础操作
 + 连接 、* 重复、s[i] 索引(index)、s[i:j] 切片(slice)、for循环遍历

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