[已解决]for循环和if语句的嵌套

一次芳

我的源程序：
names=['mother','teacher','student','father']
identity=input("please entry your identity:")
if identity not in names:
    print("unidentifiable, systen not record your identity")
else:
    for name in names:
        if identity==name:
            print("you are a "+identity.title()+",today you should clean honse.")
        elif identity==name:
            print("you are a "+identity.title()+",today you should standy.")
        elif identity==name:
            print("you are a "+identity.title()+",today you should teach your student.")
        else:
            print("you are a "+identity.title()+",today you should work.")
   
我的运行结果：
please entry your identity:student
you are a Student,today you should work.
you are a Student,today you should work.
you are a Student,today you should clean honse.
you are a Student,today you should work.

问题：不是应该输出   you are a Student，today you should standy   
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最佳答案

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thexiosi

2018-5-26 14:49:25

hi 原因如下

1. names=['mother','teacher','student','father']
   
2. identity=input("please entry your identity:")
   
3. if identity not in names:
   
4.     print("unidentifiable, systen not record your identity")
   
5. else:
   
6.     #for name in names:# here 此处用for循环，引发逻辑混乱。需要进行修正
   
7.     print(identity)
   
8.     if identity==names[0]:
   
9.         print("you are a "+identity.title()+",today you should clean honse.")
   
10.     elif identity==names[2]:
    
11.         print("you are a "+identity.title()+",today you should standy.")
    
12.     elif identity==names[1]:
    
13.         print("you are a "+identity.title()+",today you should teach your student.")
    
14.     else:
    
15.         print("you are a "+identity.title()+",today you should work.")
    

复制代码

please entry your identity:student
student
you are a Student,today you should standy.

跳转到最佳答案楼层

thexiosi

hi 原因如下

1. names=['mother','teacher','student','father']
   
2. identity=input("please entry your identity:")
   
3. if identity not in names:
   
4.     print("unidentifiable, systen not record your identity")
   
5. else:
   
6.     #for name in names:# here 此处用for循环，引发逻辑混乱。需要进行修正
   
7.     print(identity)
   
8.     if identity==names[0]:
   
9.         print("you are a "+identity.title()+",today you should clean honse.")
   
10.     elif identity==names[2]:
    
11.         print("you are a "+identity.title()+",today you should standy.")
    
12.     elif identity==names[1]:
    
13.         print("you are a "+identity.title()+",today you should teach your student.")
    
14.     else:
    
15.         print("you are a "+identity.title()+",today you should work.")
    

复制代码

please entry your identity:student
student
you are a Student,today you should standy.

一次芳

thexiosi 发表于 2018-5-26 14:49
hi 原因如下

elif结构的选择语句，当碰到第一个合法的条件时，剩下的条件便不会再判断了，那循环到name为student时不是只应该打印you are a student ,today you should clean house吗？
试了一下还是不行
改了之后结果是这样的
please entry your identity:student
you are a Student,today you should work.
you are a Student,today you should work.
you are a Student,today you should work.
you are a Student,today you should work.

ba21

这么不合理的代码。。。。。。。

假设你identity ="student"   name = "student"

if identity==name: #输出
            print("you are a "+identity.title()+",today you should clean honse.")
        elif identity==name: #输出
            print("you are a "+identity.title()+",today you should standy.")
        elif identity==name: #输出
            print("you are a "+identity.title()+",today you should teach your student.")
        else:
            print("you are a "+identity.title()+",today you should work.")

上面 if identity==name elif  identity==name 都一样的条件，还elif干嘛？多此一举。

修改你的代码

1. 
   
2. names=['mother','teacher','student','father']
   
3. identity=input("please entry your identity:")
   
4. 
   
5. if identity not in names:
   
6.     print("unidentifiable, systen not record your identity")
   
7. else:
   
8.     for name in names:
   
9.         if identity==name:
   
10.             print("you are a "+identity+",today you should clean honse.")
    
11.             break
    
12.         if identity==name:
    
13.             print("you are a "+identity+",today you should standy.")
    
14.             break
    
15.         if identity==name:
    
16.             print("you are a "+identity+",today you should teach your student.")
    
17.             break
    
18.         if identity==name:
    
19.             print("you are a "+identity+",today you should work.")
    
20.             break
    

复制代码

一次芳

ba21 发表于 2018-5-26 15:06
这么不合理的代码。。。。。。。

假设你identity ="student"   name = "student"

谢谢哈，但是改了之后结果依然不是我想要的。。。
我输入student   应该打印的是 you are a student,today you should stanty
但是按照你的修改，输出的是you are a student，today you should clean honose,

一次芳

感谢各位，我已经找到原因了
names=['mother','teacher','student','father']
identity=input("please entry your identity:")
if identity not in names:
    print("unidentifiable, systen not record your identity")
else:
    if names[0]==identity:
            print("you are a "+identity.title()+",today you should clean honse.")
    elif names[1]==identity:
            print("you are a "+identity.title()+",today you should standy.")
    elif names[2]==identity:
            print("you are a "+identity.title()+",today you should teach your student.")
    else:
            print("you are a "+identity.title()+",today you should work.")

新手·ing

一次芳 发表于 2018-5-26 15:33
感谢各位，我已经找到原因了
names=['mother','teacher','student','father']
identity=input("p ...

这不是闲的吗，直接字符串判断啊。