python学习笔记

小tip：循环中尽量不要使用多的break和continue，会使分支变多，程序变得复杂，更容易出错

疑问

1.代码中传入错误的参数，和python解释器中传入错误的参数，提示语不一致

def my_abs(x):
    if not isinstance(x, (int, float)):
        raise TypeError('bad operand type')
    if x >= 0:
        return x
    else:
        return -x
my_abs('A')

运行结果是;

C:UsersuserDesktop>python C:UsersuserDesktophello.py
Traceback (most recent call last):
  File "C:UsersuserDesktophello.py", line 10, in <module>
    my_abs('A')
  File "C:UsersuserDesktophello.py", line 5, in my_abs
    raise TypeError('bad operand type')
TypeError: bad operand type

　　

代码是

def my_abs(x):
    if not isinstance(x, (int, float)):
        raise TypeError('bad operand type')
    if x >= 0:
        return x
    else:
        return -x

　　

解释器中运行，提示语不同

>>> from hello import my_abs
>>> my_abs('a')
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "C:UsersuserDesktophello.py", line 4, in my_abs
    if not isinstance(x,(int,float)):
TypeError: '>' not supported between instances of 'str' and 'int'

　

参数笔记

　参数定义的顺序必须是：必选参数、默认参数、可变参数、命名关键字参数和关键字参数。

https://ai.google/research/pubs/pub62

mapreduce论文