发布于 2014-12-21 17:56:56 | 4485 次阅读 | 评论: 1 | 来源: PHPERZ

这里有新鲜出炉的Python3 官方中文指南,程序狗速度看过来!

Python编程语言

Python 是一种面向对象、解释型计算机程序设计语言,由Guido van Rossum于1989年底发明,第一个公开发行版发行于1991年。Python语法简洁而清晰,具有丰富和强大的类库。它常被昵称为胶水语言,它能够把用其他语言制作的各种模块(尤其是C/C++)很轻松地联结在一起。


本文为大家整理总结了一些常见的python错误大全,感兴趣的同学参考下。

+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

In [105]: T1 = (1)  
In [106]: T2 = (2,3)  
In [107]: T1 + T2  
---------------------------------------------------------------------------  
TypeError                                 Traceback (most recent call last)  
<ipython-input-107-b105c7b32d90> in <module>()  
----> 1 T1 + T2;  
  
TypeError: unsupported operand type(s) for +: 'int' and 'tuple'

【错误分析】(1)的类型是整数,所以不能与另一个元祖做合并操作,如果只有一个元素的元祖,应该用(1,)来表示

    In [108]: type(T1)  
    Out[108]: int  
      
    In [109]: T1 = (1,)  
    In [110]: T2 = (2,3)  
    In [111]: T1 + T2  
    Out[111]: (1, 2, 3)  

+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

>>> hash(1,(2,[3,4]))  
  
Traceback (most recent call last):  
  File "<pyshell#95>", line 1, in <module>  
    hash((1,2,(2,[3,4])))  
TypeError: unhashable type: 'list' 

【错误分析】字典中的键必须是不可变对象,如(整数,浮点数,字符串,元祖),可用hash()判断某个对象是否可哈希

    >>> hash('string')  
    -1542666171  

但列表中元素是可变对象,所以是不可哈希的,所以会报上面的错误.如果要用列表作为字典中的键,最简单的办法是:

>>> D = {}  
>>> D[tuple([3,4])] = 5  
>>> D  
{(3, 4): 5} 

+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

    >>> L = [2,1,4,3]  
    >>> L.reverse().sort()  
    Traceback (most recent call last):  
      File "<stdin>", line 1, in <module>  
    AttributeError: 'NoneType' object has no attribute 'sort'  
    >>> L  
    [3, 4, 1, 2]  

【错误分析】列表属于可变对象,其append(),sort(),reverse()会在原处修改对象,不会有返回值,或者说返回值为空,
所以要实现反转并排序,不能并行操作,要分开来写

    >>> L = [2,1,4,3]  
    >>> L.reverse()  
    >>> L.sort()  
    >>> L  
    [1, 2, 3, 4]  

或者用下面的方法实现:

    In [103]: sorted(reversed([2,1,4,3]))  
    Out[103]: [1, 2, 3, 4]  

+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

    >>> class = 78  
    SyntaxError: invalid syntax  

【错误分析】class是Python保留字,Python保留字不能做变量名,可以用Class,或klass
同样,保留字不能作为模块名来导入,比如说,有个and.py,但不能将其作为模块导入

    >>> import and  
    SyntaxError: invalid syntax  

+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

    >>> f = open('D:\new\text.data','r')  
    Traceback (most recent call last):  
      File "<stdin>", line 1, in <module>  
    IOError: [Errno 22] invalid mode ('r') or filename: 'D:\new\text.data'  
    >>> f = open(r'D:\new\text.data','r')  
    >>> f.read()  
    'Very\ngood\naaaaa'  

【错误分析】\n默认为换行,\t默认为TAB键,所以在D:\目录下找不到ew目录下的ext.data文件,将其改为raw方式输入即可。
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

    try:  
        print 1 / 0  
          
    except ZeroDivisionError:  
        print 'integer division or modulo by zero'  
          
    finally:  
        print 'Done'  
      
    else:    
        print 'Continue Handle other part'  
    报错如下:  
    D:\>python Learn.py  
      File "Learn.py", line 11  
        else:  
           ^  
    SyntaxError: invalid syntax  

【错误分析】错误原因,else, finally执行位置;正确的程序应该如下:

    try:  
        print 1 / 0  
          
    except ZeroDivisionError:  
        print 'integer division or modulo by zero'  
      
      
    else:    
        print 'Continue Handle other part'  
          
    finally:  
        print 'Done'  

+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

    >>> [x,y for x in range(2) for y in range(3)]  
      File "<stdin>", line 1  
        [x,y for x in range(2) for y in range(3)]  
               ^  
    SyntaxError: invalid syntax  

【错误分析】错误原因,列表解析中,x,y必须以数组的方式列出(x,y)

    >>> [(x,y) for x in range(2) for y in range(3)]  
    [(0, 0), (0, 1), (0, 2), (1, 0), (1, 1), (1, 2)]  

+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

    class JustCounter:  
        __secretCount = 0  
      
        def count(self):  
            self.__secretCount += 1  
            print 'secretCount is:', self.__secretCount  
      
    count1 = JustCounter()  
      
    count1.count()  
    count1.count()  
      
    count1.__secretCount  

报错如下:

    >>>   
    secretCount is: 1  
    secretCount is: 2  
      
      
    Traceback (most recent call last):  
      File "D:\Learn\Python\Learn.py", line 13, in <module>  
        count1.__secretCount  
    AttributeError: JustCounter instance has no attribute '__secretCount'    

【错误分析】双下划线的类属性__secretCount不可访问,所以会报无此属性的错误.

解决办法如下:

    # 1. 可以通过其内部成员方法访问  
    # 2. 也可以通过访问  
    ClassName._ClassName__Attr  
    #或   
    ClassInstance._ClassName__Attr  
    #来访问,比如:  
    print count1._JustCounter__secretCount  
    print JustCounter._JustCounter__secretCount   

+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

    >>> print x  
    Traceback (most recent call last):  
      File "<stdin>", line 1, in <module>  
    NameError: name 'x' is not defined  
    >>> x = 1  
    >>> print x  
    1  

【错误分析】Python不允许使用未赋值变量
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

    >>> t = (1,2)  
    >>> t.append(3)  
    Traceback (most recent call last):  
      File "<stdin>", line 1, in <module>  
    AttributeError: 'tuple' object has no attribute 'append'  
    >>> t.remove(2)  
    Traceback (most recent call last):  
      File "<stdin>", line 1, in <module>  
    AttributeError: 'tuple' object has no attribute 'remove'  
    >>> t.pop()  
    Traceback (most recent call last):  
      File "<stdin>", line 1, in <module>  
    AttributeError: 'tuple' object has no attribute 'pop'  

【错误分析】属性错误,归根到底在于元祖是不可变类型,所以没有这几种方法.
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

    >>> t = ()  
    >>> t[0]  
    Traceback (most recent call last):  
      File "<stdin>", line 1, in <module>  
    IndexError: tuple index out of range  
    >>> l = []  
    >>> l[0]  
    Traceback (most recent call last):  
      File "<stdin>", line 1, in <module>  
    IndexError: list index out of range  

【错误分析】空元祖和空列表,没有索引为0的项
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

    >>> if X>Y:  
    ...  X,Y = 3,4  
    ...   print X,Y  
      File "<stdin>", line 3  
        print X,Y  
        ^  
    IndentationError: unexpected indent  
      
      
    >>>   t = (1,2,3,4)  
      File "<stdin>", line 1  
        t = (1,2,3,4)  
        ^  
    IndentationError: unexpected indent  

【错误分析】一般出在代码缩进的问题
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

    >>> f = file('1.txt')  
    >>> f.readline()  
    'AAAAA\n'  
    >>> f.readline()  
    'BBBBB\n'  
    >>> f.next()  
    'CCCCC\n'  

【错误分析】如果文件里面没有行了会报这种异常

    >>> f.next() #  
    Traceback (most recent call last):  
      File "<stdin>", line 1, in <module>  
    StopIteration  

有可迭代的对象的next方法,会前进到下一个结果,而在一系列结果的末尾时,会引发StopIteration的异常.

+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

    >>> string = 'SPAM'  
    >>> a,b,c = string  
    Traceback (most recent call last):  
      File "<stdin>", line 1, in <module>  
    ValueError: too many values to unpack  

【错误分析】接受的变量少了,应该是

    >>> a,b,c,d = string  
    >>> a,d  
    ('S', 'M')  
    #除非用切片的方式  
    >>> a,b,c = string[0],string[1],string[2:]  
    >>> a,b,c  
    ('S', 'P', 'AM')  
    或者  
    >>> a,b,c = list(string[:2]) + [string[2:]]  
    >>> a,b,c  
    ('S', 'P', 'AM')  
    或者  
    >>> (a,b),c = string[:2],string[2:]  
    >>> a,b,c  
    ('S', 'P', 'AM')  
    或者  
    >>> ((a,b),c) = ('SP','AM')  
    >>> a,b,c  
    ('S', 'P', 'AM')  
      
    简单点就是:  
    >>> a,b = string[:2]  
    >>> c   = string[2:]  
    >>> a,b,c  
    ('S', 'P', 'AM')  

+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

    >>> mydic={'a':1,'b':2}  
    >>> mydic['a']  
    1  
    >>> mydic['c']  
    Traceback (most recent call last):  
      File "<stdin>", line 1, in ?  
    KeyError: 'c'  

【错误分析】当映射到字典中的键不存在时候,就会触发此类异常, 或者可以,这样测试

    >>> 'a' in mydic.keys()  
    True  
    >>> 'c' in mydic.keys()              #用in做成员归属测试  
    False  
    >>> D.get('c','"c" is not exist!')   #用get或获取键,如不存在,会打印后面给出的错误信息  
    '"c" is not exist!'  

+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

    File "study.py", line 3  
      return None  
      ^  
    dentationError: unexpected indent  

【错误分析】一般是代码缩进问题,TAB键或空格键不一致导致

+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

    >>>def A():  
    return A()  
    >>>A() #无限循环,等消耗掉所有内存资源后,报最大递归深度的错误    
    File "<pyshell#2>", line 2, in A return A()RuntimeError: maximum recursion depth exceeded  
    class Bird:  
        def __init__(self):  
            self.hungry = True  
        def eat(self):  
            if self.hungry:  
                print "Ahaha..."  
                self.hungry = False  
            else:  
                print "No, Thanks!"  


该类定义鸟的基本功能吃,吃饱了就不再吃  
输出结果:  

    >>> b = Bird()  
    >>> b.eat()  
    Ahaha...  
    >>> b.eat()  
    No, Thanks!  


下面一个子类SingBird,  

    class SingBird(Bird):  
        def __init__(self):  
            self.sound = 'squawk'  
        def sing(self):  
            print self.sound  


输出结果:  
 

    >>> s = SingBird()  
    >>> s.sing()  
    squawk  
    SingBird是Bird的子类,但如果调用Bird类的eat()方法时,  
    >>> s.eat()  
    Traceback (most recent call last):  
      File "<pyshell#5>", line 1, in <module>  
        s.eat()  
      File "D:\Learn\Python\Person.py", line 42, in eat  
        if self.hungry:  
    AttributeError: SingBird instance has no attribute 'hungry'  

【错误分析】代码错误很清晰,SingBird中初始化代码被重写,但没有任何初始化hungry的代码

    class SingBird(Bird):  
        def __init__(self):  
            self.sound = 'squawk'  
            self.hungry = Ture #加这么一句  
        def sing(self):  
            print self.sound  

+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

    class Bird:  
        def __init__(self):  
            self.hungry = True  
        def eat(self):  
            if self.hungry:  
                print "Ahaha..."  
                self.hungry = False  
            else:  
                print "No, Thanks!"  
      
    class SingBird(Bird):  
        def __init__(self):  
            super(SingBird,self).__init__()  
            self.sound = 'squawk'  
        def sing(self):  
            print self.sound  
    >>> sb = SingBird()  
    Traceback (most recent call last):  
      File "<pyshell#5>", line 1, in <module>  
        sb = SingBird()  
      File "D:\Learn\Python\Person.py", line 51, in __init__  
        super(SingBird,self).__init__()  
    TypeError: must be type, not classobj  

【错误分析】在模块首行里面加上__metaclass__=type,具体还没搞清楚为什么要加

    __metaclass__=type  
    class Bird:  
        def __init__(self):  
            self.hungry = True  
        def eat(self):  
            if self.hungry:  
                print "Ahaha..."  
                self.hungry = False  
            else:  
                print "No, Thanks!"  
      
    class SingBird(Bird):  
        def __init__(self):  
            super(SingBird,self).__init__()  
            self.sound = 'squawk'  
        def sing(self):  
            print self.sound  
    >>> S = SingBird()  
    >>> S.  
    SyntaxError: invalid syntax  
    >>> S.  
    SyntaxError: invalid syntax  
    >>> S.eat()  
    Ahaha...  

+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

   >>> T  
    (1, 2, 3, 4)  
    >>> T[0] = 22   
    Traceback (most recent call last):  
      File "<pyshell#129>", line 1, in <module>  
        T[0] = 22  
    TypeError: 'tuple' object does not support item assignment  

【错误分析】元祖不可变,所以不可以更改;可以用切片或合并的方式达到目的.

    >>> T = (1,2,3,4)  
    >>> (22,) + T[1:]  
    (22, 2, 3, 4)  

+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++



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