Python 自学的日子--One day笔记- 字符串拼接 + if while for循环

标签：

注释
单行注释 #
多行注释 ‘‘‘ 三个单引号或者三个双引号 """

‘‘‘ 用三引号引住可以多行赋值

用户交互 input

字符串拼接
+  ""%() "".format()推荐使用
name = input("name:")
age = int(input("age:"))
sex = input("sex:")
例：+
# 字符串拼接+
info1 = ‘‘‘----info in ‘‘‘ + name + ‘‘‘---
name:‘‘‘ + name + ‘‘‘
age:‘‘‘ + age + ‘‘‘
sex:‘‘‘ + sex + ‘‘‘
‘‘‘
例：""%()
# %格式化字符串
info = ‘‘‘------info in %s -------
name:%s
age:%d
sex:%s
‘‘‘ % ("name", "name", age, "sex")

#"".format()
info3 = ‘‘‘---info in {_name}---
name:{_name}
age:{_age}
sex:{_sex}
‘‘‘.format(_name=name,
           _age=age,
           _sex=sex)
info4 = ‘‘‘---info in {0}---
name:{0}
age:{1}
sex:{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

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
（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

Python 自学的日子--One day笔记- 字符串拼接 + if while for循环

标签：

原文地址：http://www.cnblogs.com/Upward-man/p/5754293.html