python学习_常用语句

时间：2023-02-07 00:30:55

1.变量 

1 1 name='hu qihang'                     #变量名应为英文，方便阅读
2 2 name_of_gf='chen ye'                 #多个单词用下划线隔开
3 3 名字='hu qihang'                      #变量名可以是中文
4 4 NAME='hu qihang'                     #常量用大写，值是可变的，只是告诉你不要变
5 5 print(name,name_of_gf,名字,NAME,sep='\n')

 

  2.打印

1 sum='''
2 name='hu qihang'
3 名字='hu qihang'
4 NAME='hu qihang'
5 '''                                  #三引号可以多行输出，单独使用为注释
6 print(sum)

 

3.字符串格式化

3.1 %s

 1 name=input('your name:')             #用户输入input，输入的默认是字符串
 2 age=input('your age:')
 3 job=input('your job:')
 4 info='''
 5 ------info of %s-----
 6 Name:%s
 7 Age:%s
 8 Job:%s
 9 '''%(name,name,age,job)              #字符串格式化，%s字符串占位符，%d整型占位符，%f浮点型占位符，单一一个%s，可以直接%变量
10 print(info)

 

3.2 format

3.2.1 format

 1 name=input('your name:')
 2 age=input('your age:')
 3 job=input('your job:')
 4 info='''
 5 ------info of {Name}-----
 6 Name:{Name}
 7 Age:{Age}
 8 Job:{Job}
 9 '''.format(Name=name,Age=age,Job=job)            #可以赋参数也可以不赋，不赋参数的话要按顺序写变量
10 print(info)

 

3.2.2 format_map

 

1 info='my name is {name},i am {years} old'
2 print(info.format_map({'name':'huqihang','years':'18'}))      #括号里面是字典

 

4.getpass

1 import getpass
2 
3 username=input('your username:')
4 password=getpass.getpass('your password:')      #getpass输入时是秘文，在pycharm中不好用，
5 
6 print(username,password)

 

5.条件

5.1 if-else

1 _username='huqihang'
2 _password='123abc'
3 username=input('your username:')
4 password=input('your password:')
5 if username==_username and password==_password:
6     print('welcome user {Name} login!'.format(Name=username))
7 else:
8     print('invalid username or password!')

 

5.2 elif

1 age_of_huqihang=23
2 guess_age=int(input('guess age:'))
3 if guess_age==age_of_huqihang:
4     print('yes')
5 elif guess_age>age_of_huqihang:
6     print('smaller')
7 else:
8     print('bigger')

 

 

6.循环
 

6.1 while
 

6.1.1 三次机会猜数字
 

 
 
 1 age_of_huqihang=23
 2 count=1
 3 while count<4:
 4     guess_age=int(input('guess age:'))
 5     if guess_age==age_of_huqihang:
 6         print('yes')
 7         break
 8     elif guess_age>age_of_huqihang:
 9         print('smaller')
10     else:
11         print('bigger')
12     count=count+1
13 else:
14     print('you have tried too many times!')
 




 
 

6.1.2 任意次机会猜数字
 

 
 
 1 age_of_huqihang=23
 2 count=1
 3 while count<4:
 4     guess_age=int(input('guess age:'))
 5     if guess_age==age_of_huqihang:
 6         print('yes')
 7         break
 8     elif guess_age>age_of_huqihang:
 9         print('smaller')
10     else:
11         print('bigger')
12     count=count+1
13     if count==4:
14         continue_try=input('do you want to guessing.y/n')
15         if continue_try=='y':
16             count=1
17         else:
18             print('lost!')
 

 

 
 

6.2 for
 

6.2.1三次机会猜数字
 

 
 
 1 age_of_huqihang=23
 2 for i in range(3):
 3     guess_age=int(input('guess age:'))
 4     if guess_age==age_of_huqihang:
 5         print('yes')
 6         break                             #结束当前循环。多重循环时，结束当前循环，并不是结束所有循环
 7     elif guess_age>age_of_huqihang:
 8         print('smaller')
 9     else:
10         print('bigger')
11 else:                                     #for循环的else是执行完循环以后就运行else语句，如果break了，就跳出for不执行else
12     print('you have tried too many times!')
 

 

 
 

6.2.2步长
 

 1 for i in range(0,10,2):         #从0到10，不包括10，2是步长，打印一个跳一个，默认是1



  2     print(i)     
 

6.3 break和continue
 

6.3.1 break
 

 
 
1 for i in range(0,10):
2     if i<3:
3         print(i)
4     else:
5         break                             #结束当前循环
6     print('oops')
 

 

 
 

6.3.2 continue
 

 
 
1 for i in range(0,10):
2     if i<3:
3         print(i)
4     else:
5         continue                         #跳出本次循环，继续下次循环
6     print('oops')
 

 

 
 

 
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