• 只要重写了 __str__()方法，不管是打印对象还是打印对象的字符串格式，其调用的都是 __str__()方法，所以显示的都是重写的__str__()结果。也就是说，print(str(obj)) 和 print(obj) 是一样的。

• 而只有在控制台（window下的cmd，命令提示符）中，在python环境下直接输入（不是打印）obj，回车，调用的才是 __repr__()方法。如果没有重写该方法，还是会显示对象所在的地址。

__count是类属性，如果将print(dog.__count)放到cat对象建立后面，将打印出2.因为cat对象建立后，Animal的属性__count就变了，dog能访问__count属性，所以就变了。

# Enter a code

from functools import reduce

result =  [item for item in map(lambda x:x*x,[1,2,3,4,5,6])]

print (result)

print reduce(lambda x,y:x+y,[1,3,5,7,9])

print sorted(['bob','MD','22A','QQ','mm'],key=lambda item:item.lower(),reverse = True)

# Enter a code

L=[2,4,1,45,12,33,11,44,21]

K=['aad','']

print sorted(L)

def k(item):

    return item.lower()

print sorted(['Bod','UUU1PPP','qqasd'],key=k ,reverse=True)

2我为1wee

# Enter a code

import math

def is_odd(x):

    return x%2 ==1

for item in filter(is_odd,[1,6,9,54,52,2,4,8,7]):

    print(item)

def  is_empty(s):

     return s   and len(s.strip())>0

L =['te  st',None,'  str','','  ','END']    

for item1 in filter (is_empty,L):

    print(item1)

def sqr(x):

    r = int(math.sqrt(x))

    return r*r == x

for item2 in filter(sqr,(range(1,101))):

    print item2

from functools import reduce

def f(x,y):

    return x*y

print(reduce(f,[1,3,5,7,9,12,4,5,100,7894,7896321,789456123]))

# Enter a code

import math

def  add(x,y,f):

    return f(x)+f(y)

print(add(81,64,math.sqrt))

python -m http.server 9999 -d C:/

lass op(object):
   def ok(num):
       f = open('ok1.txt',mode='a') #读取中文
       f.writelines('\n'+num)
       f.close()
       e = open('ok81.txt',mode='a+')
       e.writelines(num+'\n')
       e.close();
       gl = open('ok81.txt',mode='r')

       content = gl.readlines()
       print(content)
       gl.close()

class op(object):
   def ok(num):
       f = open('ok1.txt',mode='w') #读取中文
       f.writelines(num)
       f.close()

import os


class op(object):
   def ok(num):
       f = open('ok1.txt',  encoding='utf-8') #读取中文

       s = f.read(num)
       l= f.readlines()
       print(s)
       print(l)

       f.close()

线下已实现

#opfile.py

import os
class op(object):
   def ok():
      f = open('ok81.txt', 'x')
      print ('ok92')
      f.close()

#main.py

import opfile

# This is a sample Python script.

# Press Shift+F10 to execute it or replace it with your code.
# Press Double Shift to search everywhere for classes, files, tool windows, actions, and settings.





def print_hi(name):
   # Use a breakpoint in the code line below to debug your script.
   print(f'Hi, {name}')  # Press Ctrl+F8 to toggle the breakpoint.


# Press the green button in the gutter to run the script.
if __name__ == '__main__':
   print_hi('PyCharm')

# See PyCharm help at https://www.jetbrains.com/help/pycharm/
num = input('pls input the num:'+'\n')
print('this is num is:{}'.format(num))
opfile.op.ok();

class person(object):

    def __init__(self,name,gender):

        self.name = name

        self.gender = gender

    def __call__(self,friend):

        print('my name is {}...'.format(self.name))

        print('my friend is {}...'.format(friend))

p= person('alice','female')

p('box')

看不懂