Notes and conditional (flow control statements) exercises

Note

• For some obscure or interpreted code label
• PEP8, can not exceed the specified line

1. 单行注释： # xxx

2. 多行注释： 
    """
    xxx
    """

3. ctrl+/  直接把圈起来的部分改成注释

Analyzing conditions (process control statements)

• = Is the assignment;
• == is equal;
• ! = Is not equal to
• : Means the end of the statement
• Indent: 4 spaces = tab
• tab and space can not be mixed, otherwise it is difficult to find errors
• 1个IF，if+else，if+elif+elif, if+elif+else, if嵌套, if+if+if+if

1. sex=input("请输入你的性别：")
   if sex == "girl":    
    print("come on,baby!")
   else:    
    print("go and find Xiaoming Huang, he is the same guy with you")

2. sex=input("请输入你的性别：")
   if sex == "man":    
    print("bye")
   elif sex == "girl":    
    print("come on,baby!")
   else:    
    print("go and find Xiaoming Huang, he is the same guy with you")

3. sex=input("请输入你的性别：")  man
   if sex == "girl":    
    print("come on,baby!")

   • if the statement is not necessary to keep else, such as 3 can not output.

4. practice

   num=input("请输入你的年龄：")
   number=int(num)
   if number > 18 and number < 25:
       print("come on,baby!")
   else:
       print("That's not good")
   
   
   name=input("请输入你的名字：")
   password=input("请输入你的密码：")
   if name != "alex" or password != "oldboy":
       print("There is some wrong with your name or password!")
   else:
       print("land successfully")
   
   
   sex = input("请输入你的性别：")
   if sex == "man":
       print("go out and fuck yourself")
   else:
       age = int(input("请输入你的年龄："))
       if age <= 25:
           print("hello")
       else:
           print("sorry,i`m so tired.")
   print("that`s a good night")

   • ! = Is py3 of inequality

   • 

   • Else if there is, then there will certainly be an output, ie, the "alternative"

5. if nested

   • If the condition:

   • If the condition indent:

     Indent results

     

6. if if if

   constant

   • Constants: variable name capitalization is constant. (In the definition of non python, the python constants do not exist) eg: ID
   • You may be modified, but do not change as much as possible
   • For the configuration file