Python随笔(四)、python基础
05 python s12 day4 迭代器原理及使用 什么是迭代： 可以直接作用于for循环的对象统称为可迭代对象(Iterable)。* 可以被next()函数调用并不断返回下一个值的对象称为迭代器(Iterator)。 所有的Iterable均可以通过内置函数iter()来转变为Iterator。 对迭代器来讲，有一个next()就够了。在你使用for 和 in 语句时，程序就会自动调用即将被处理的对象的迭代器对象，然后使用它的next()方法，直到监测到一个StopIteration异常。
#!usr/bin/env python #-- coding:utf-8 _- """ @author:Administrator @file: 迭代器.py @time: 2018/01/01 """ names = iter(['alex','xsb','zsb','dsb']) print(names) print(names.next()) print(names.next()) print(names.next()) print(names.next()) 返回结果： E:\Python36\python.exe C:/Users/Administrator/PycharmProjects/2018-01-01/迭代器.py <list_iterator object at 0x00000000026DC470> alex xsb zsb dsb
06 python s12 day4 生成器的使用 def cash_money(amount): while amount >0: amount -=100 yield 100 print("又来取钱了？")
atm = cash_money(600) print(type(atm)) print(atm.next()) print(atm.next()) print("叫个大保健") print(atm.next()) print(atm.next()) print(atm.next()) print(atm.next()) 返回结果： E:\Python36\python.exe C:/Users/Administrator/PycharmProjects/2018-01-01/迭代器.py <class 'generator'> 100 又来取钱了？ 100 叫个大保健 又来取钱了？ 100 又来取钱了？ 100 又来取钱了？ 100 又来取钱了？ 100
07 python s12 day4 使用yield实现单线程中的异步并发效果 注意:yield和break的区别 #!usr/bin/env python #-- coding:utf-8 _- """ @author:Administrator @file: yield迭代器.py @time: 2018/01/01 """ import time def consumer(name): print("%s 准备吃包子了!" %name) while True: baozi = yield print("包子[%s]来了，被[%s]吃了" %(baozi,name))
def producer(name): c = consumer('A') c2 = consumer('B') c.next() c2.next() print("老子准备开始做包子了！") for i in range(10): time.sleep(1) print("做了2个包子！") c.send('Tenglan') c2.send(i)
producer("alex") 返回结果: E:\Python36\python.exe C:/Users/Administrator/PycharmProjects/2018-01-01/yield迭代器.py A 准备吃包子了! B 准备吃包子了! 老子准备开始做包子了！ 做了2个包子！ 包子[Tenglan]来了，被[A]吃了 包子[0]来了，被[B]吃了 做了2个包子！ 包子[Tenglan]来了，被[A]吃了 包子[1]来了，被[B]吃了 做了2个包子！ 包子[Tenglan]来了，被[A]吃了 包子[2]来了，被[B]吃了 做了2个包子！ 包子[Tenglan]来了，被[A]吃了 包子[3]来了，被[B]吃了 做了2个包子！ 包子[Tenglan]来了，被[A]吃了 包子[4]来了，被[B]吃了 做了2个包子！ 包子[Tenglan]来了，被[A]吃了 包子[5]来了，被[B]吃了 做了2个包子！ 包子[Tenglan]来了，被[A]吃了 包子[6]来了，被[B]吃了 做了2个包子！ 包子[Tenglan]来了，被[A]吃了 包子[7]来了，被[B]吃了 做了2个包子！ 包子[Tenglan]来了，被[A]吃了 包子[8]来了，被[B]吃了 做了2个包子！ 包子[Tenglan]来了，被[A]吃了 包子[9]来了，被[B]吃了
08 python s12 day4 装饰器原理介绍和基本实现 http://www.cnblogs.com/wupeiqi/articles/4980620.html 2、需求来了 初创公司有N个业务部门，1个基础平台部门，基础平台负责提供底层的功能，如：数据库操作、redis调用、监控API等功能。业务部门使用基础功能时，只需调用基础平台提供的功能即可。如下： ############### 基础平台提供的功能如下 ###############
def f1(): print 'f1'
def f2(): print 'f2'
def f3(): print 'f3'
def f4(): print 'f4'
############### 业务部门A 调用基础平台提供的功能 ###############
f1() f2() f3() f4()
############### 业务部门B 调用基础平台提供的功能 ###############
f1() f2() f3() f4()
作用，给已经存在的功能扩展新的功能
09 python s12 day4 装饰器实现 装饰器代码: #!usr/bin/env python #-- coding:utf-8 _- """ @author:Administrator @file: 装饰器.py @time: 2018/01/01 """ #第一种方式 ''' def login(func): print("passwd user verification.....") return func ''' return None ''' def home(name): print("Welcome [%s] to home page" % name )br/>@login def tv(name): print("Welcome [%s] to TV page" % name ) def moive(name): print("Welcome [%s] to moive page" % name )
#tv = login(tv) tv("Alex") ''' #第二种方式: ''' def login(func): print("passwd user verification.....") return func def home(name): print("Welcome [%s] to home page" % name ) def tv(): print("Welcome [%s] to TV page" ) def moive(name): print("Welcome [%s] to moive page" % name )
tv = login(tv) tv() ''' #第三种方式: def login(func): def inner(arg): print("passwd user verification.....") func(arg) return inner
def home(name): print("Welcome [%s] to home page" % name )br/>@login def tv(name): print("Welcome [%s] to TV page" % name ) def moive(name): print("Welcome [%s] to moive page" % name )
tv("Alex") 返回结果: E:\Python36\python.exe C:/Users/Administrator/PycharmProjects/2018-01-01/装饰器.py passwd user verification..... Welcome [Alex] to TV page
10 python s12 day4 实现带参数的复杂装饰器 def login(func): def inner(arg): print("passwd user verification.....") func(arg) return inner
def home(name): print("Welcome [%s] to home page" % name )br/>@login def tv(name): print("Welcome [%s] to TV page" % name )br/>@login def moive(name): print("Welcome [%s] to moive page" % name )
tv("Alex") moive("Alex") 返回结果： E:\Python36\python.exe C:/Users/Administrator/PycharmProjects/2018-01-01/装饰器.py passwd user verification..... Welcome [Alex] to TV page passwd user verification..... Welcome [Alex] to moive page
装饰器多参数及返回值： def login(func): def inner(*args,*kwargs): print("passwd user verification.....") return func(args,**kwargs) return inner
def home(name): print("Welcome [%s] to home page" % name )br/>@login def tv(name,passwd="123"): print("Welcome [%s] to TV page" % name ) return 4br/>@login def moive(name): print("Welcome [%s] to moive page" % name )
t = tv("Alex",passwd="123") print(t) moive("Alex") 返回结果： E:\Python36\python.exe C:/Users/Administrator/PycharmProjects/2018-01-01/装饰器.py passwd user verification..... Welcome [Alex] to TV page 4 passwd user verification..... Welcome [Alex] to moive page
11 python s12 day4 递归原理及实现 #!usr/bin/env python #-- coding:utf-8 _- """ @author:Administrator @file: 递归.py @time: 2018/01/01 """ ''' def digui(n): sum = 0 if n<=0: return 1 else: return n+digui(n-1)
print(digui(30)) ''' def calc(n): print(n) if n/2 > 1: res = calc(n/2) return res
calc(100)
def calc(n): print(n) if n/2 > 1: res = calc(n/2) print('res:',res) print('N:',n) return n
calc(10)
12 python s12 day4 通过递归实现斐波那契数列 #!usr/bin/env python #-- coding:utf-8 _- """ @author:Administrator @file: 斐波那契数列.py @time: 2018/01/01 """ def func(arg1,arg2,stop): if arg1 == 0: print(arg1,arg2) arg3 = arg1 + arg2 print(arg3) if arg3< stop: func(arg2,arg3,stop)
func(0,1,100)
13 python s12 day4 算法基础之二分查找 在庞大的数据中找一个数是否在其中，比如查找65535是否在600000中。 #/usr/bin/env python #-- coding:utf-8 _- """ @author:Administrator @file: binary_search.py @time: 2018/06/30 data = list(range(1,600,3)) print (data) """
def binary_search(data_source,find_n): mid = int(len(data_source)/2) if len(data_source) >1: if data_source[mid] > find_n: print("data in left of [%s]" % data_source[mid]) binary_search(data_source[:mid],find_n) elif data_source[mid] < find_n: print("data in right of [%s]" % data_source[mid]) binary_search(data_source[mid:],find_n) else: print("find find_s",data_source[mid])
else:
print("cannot find......")if name=='main': data = list(range(1,600000)) binary_search(data,65535)
结果输出： E:\Python36\python.exe G:/PycharmProjects/basic/binary_search.py data in left of [300000] data in left of [150000] data in left of [75000] data in right of [37500] data in right of [56250] data in left of [65625] data in right of [60937] data in right of [63281] data in right of [64453] data in right of [65039] data in right of [65332] data in right of [65478] data in left of [65551] data in right of [65514] data in right of [65532] data in left of [65541] data in left of [65536] data in right of [65534] find find_s 65535
14 python s12 day4 算法基础之2维数组90度旋转 #/usr/bin/env python #-- coding:utf-8 _- """ @author:Administrator @file: erweiarr.py @time: 2018/07/01 """ #二维数组 a = [[col for col in range(4)] for row in range(4)] for i in a: print(i)
结果： E:\Python36\python.exe G:/PycharmProjects/basic/erweiarr.py [0, 1, 2, 3] [0, 1, 2, 3] [0, 1, 2, 3] [0, 1, 2, 3]
Process finished with exit code 0
2维数组90度旋转 #/usr/bin/env python #-- coding:utf-8 _- """ @author:Administrator @file: erweiarr.py @time: 2018/07/01 """ data = [[col for col in range(4)] for row in range(4)] for row in data: print(row) print("==============================") ''' [0, 1, 2, 3] [0, 1, 2, 3] [0, 1, 2, 3] [0, 1, 2, 3]
[0, 0, 0, 0] [1, 1, 1, 1] [2, 2, 2, 2] [3, 3, 3, 3] '''
for r_index,row in enumerate(data): for c_index in range(r_index,len(row)): tmp = data[c_index][r_index] data[c_index][r_index] = row[c_index] data[r_index][c_index] = tmp print('================================') for r in data: print(r)
输出结果： [0, 1, 2, 3] [0, 1, 2, 3] [0, 1, 2, 3] [0, 1, 2, 3]
================================ [0, 0, 0, 0] [1, 1, 2, 3] [2, 1, 2, 3] [3, 1, 2, 3]
[0, 0, 0, 0] [1, 1, 1, 1] [2, 2, 2, 3] [3, 3, 2, 3]
[0, 0, 0, 0] [1, 1, 1, 1] [2, 2, 2, 2] [3, 3, 3, 3]
[0, 0, 0, 0] [1, 1, 1, 1] [2, 2, 2, 2] [3, 3, 3, 3]
15 python s12 day4 正则表达式基础及计算器作业思路及要求 import re
m = re.match("abc","abcdwef") print(m)
输出结果： <_sre.SRE_Match object; span=(0, 3), match='abc'>
import re
m = re.match("abc","abcdwef") m = re.match("[0-9]","07876598jkfjkdshfjsk") m = re.match("[0-9]{0,10}","07876598jkfjkdshfjsk") m = re.findall("[0-9]{0,10}","07876598jkfjkd54645shfjsk") m = re.findall("[a-zA-Z]{1,10}","07876598jkfjkd54645shfjsk") M = re.findall(".*","07876598jkfjkd54645shfjsk") m = re.findall(".+","07876598jkfjkd54645shfjsk") m = re.findall("\S","07876598jkfjkd54645shfjsk") m = re.search("\d+","07876598jkfjkd54645shfjsk") m = re.sub("\d+","|","sdfdsfds75_45.6 4a~bc6@def",count=2) if m: print(m)