Python基础笔记-12

71.生成器 http://bbs.fishc.com/forum.php?mod=viewthread&tid=56023&highlight=yield

>>> def myGen():

   print('生成器被执行')

   yield 1

   yield 2

>>> myG=myGen()

>>> next(myG)

生成器被执行

1

>>> next(myG)

2

>>> next(myG)

Traceback (most recent call last):

 File "", line 1, in

   next(myG)

StopIteration

>>> for i in myGen():

   print(i)

生成器被执行

1

2

#用生成器解决斐波那契数列

>>> def Fibs():

   a=0

   b=1

   while True:

      a,b=b,a+b

      yield a

>>> for each in Fibs():

   if each>100:

      break

   print(each,end=' ')

1 1 2 3 5 8 13 21 34 55 89

>>>

>>>

>>> a=[i for i in range(100) if not(i%2) and i%3]

>>> a

[2, 4, 8, 10, 14, 16, 20, 22, 26, 28, 32, 34, 38, 40, 44, 46, 50, 52, 56, 58, 62, 64, 68, 70, 74, 76, 80, 82, 86, 88, 92, 94, 98]

>>>

>>> b={i:i%2==0 for i in range(10)}

>>> b

{0: True, 1: False, 2: True, 3: False, 4: True, 5: False, 6: True, 7: False, 8: True, 9: False}

>>>

>>> c={i for i in [1,1,2,3,4,5,5,6,7,8,3,2,1]}

>>> c

{1, 2, 3, 4, 5, 6, 7, 8}

>>>

>>> d='i for i in ''jjjj'''

>>>

>>> d

'i for i in jjjj'

72.模块

1）模块就是程序

2）__name__='__main__'

if __name__=='__main__' 代表本模板内部进行

包：

创建一个文件夹，文件夹的名字就是包的名字

再文件夹中创建一个__init__.py的文件，可以为空

将相关模块文件放入文件夹中

导入包：import  包名.模块名 as 模块别名

3）像个极客一样思考

73.爬虫

import urllib.request

responsed=urllib.request.urlopen('www.baidu.com')

html=responsed.read()

html=html.decode('utf-8')

print（html）

如下实战

=============================== RESTART: Shell ===============================

>>> import urllib.request

>>> response=urllib.request.urlopen('http://wwww.baidu.com')

>>> html=response.read()

>>> html=html.decode('utf-8')

>>> print(html)

例子1  猫站

import urllib.request

response=urllib.request.urlopen('http://placekitten.com/g/500/600')

cat_img=response.read()

url=response.geturl()

print(url)

info=response.info()

print(info)

code=response.getcode()

print(code)

with open('cat_500_600.jpg','wb') as f:

   f.write(cat_img)

例子2  自动翻译小程序

import urllib.request

import urllib.parse

import json

content=input('请输入需要翻译的内容')

url='http://fanyi.youdao.com/translate_o?smartresult=dict&smartresult=rule'

data={}

data['i']=content

data['from']='AUTO'

data['to']='AUTO'

data['smartresult']='dict'

data['client']='fanyideskweb'

data['salt']='1516196611674'

data['sign']='37505adea655f24b61488d0574dffee6'

data['doctype']='json'

data['version']='2.1'

data['keyfrom']='fanyi.web'

data['action']='FY_BY_CLICKBUTTION'

data['typoResult']='false'

data=urllib.parse.urlencode(data)

response=urllib.request.urlopen(url,data)

html=response.read()

target=json.loads(html)

print('翻译结果：%s'%(target['translateResult'][0][0]['tgt']))

例子3  代理ip发送请求

import urllib.request

url='http://www.whatismyip.com.tw'

proxy_support=urllib.request.ProxyHandler({'http':'138.19.213.172:80'})

opener=urllib.request.build_opener(proxy_support)

urllib.request.install_opener(opener)

response=urllib.request.urlopen(url)

html=response.read().decode('urf-8')

print(html)

例子4 妹子图抓取

import urllib.request

import os

def url_open(url):

   req=urllib.request.Request(url)

   req.add_header('User-Agent','Mozilla/5.0 (Windows NT 10.0; …) Gecko/20100101 Firefox/57.0')

   response=urllib.request.urlopen(url)

   html=response.read()

   return html   

def get_page(url):

   html=url_open(url).decode('utf-8')

   a=html.find('current-comment-page')+23

   b=html.find(']',a)

   print(html[a:b])

   return html[a:b]

def find_imgs(url):

   html=url_open(url).decode('utf-8')

   img_addrs=[]

   a=html.find('img src')

   while a!=-1:

       b=html.find('jpg',a)

       if b!=-1:

           img_addrs.append(html[a+9:b+4])

       else:

           b=a+9

       a=html.find('img src',b)

   return img_addrs

def save_imgs(folder,img_addrs):

   for each in img_addrs:

       filename=each.split('/')[-1]

       with open(filename,'wb')as f:

           img=url_open(each)

           f.write(img)

def download_mm(folder='xx',pages=10):

   os.mkdir(folder)

   os.chdir(folder)

   url='http://jiandan.net/ooxx'

   page_num=int(get_page(url))

   for i in range(pages):

       page_num-=i

       page_url=url+'/page-'+str(page_num)+'#comments'

       img_addrs=find_imgs(page_url)

       save_imgs(folder,img_addrs)

if __name__=='__main__':

   download_mm()

74 正则表达式

1.第一部分

>>> import re

>>> re.search(r'FishC','I love FishC.com!')

<_sre.SRE_Match object; span=(7, 12), match='FishC'>

>>> 'I love FisjC.com!'.find('FishC')

-1

>>> 'I love FishC.com!'.find('FishC')

7

>>> re.search(r'.','I love FishC.com!')

<_sre.SRE_Match object; span=(0, 1), match='I'>

>>> re.search(r'Fish.','I love FishC.com!')

<_sre.SRE_Match object; span=(7, 12), match='FishC'>

>>> re.search(r'\.','I love FishC.com!')

<_sre.SRE_Match object; span=(12, 13), match='.'>

>>> re,search(r'\d','I love 123 FishC.com!')

Traceback (most recent call last):

 File "", line 1, in

  re,search(r'\d','I love 123 FishC.com!')

NameError: name 'search' is not defined

>>> re.search(r'\d','I love 123 FishC.com!')

<_sre.SRE_Match object; span=(7, 8), match='1'>

>>> re.search(r'\d\d\d\.\d\d\d\.\d\d\d','192.168.111.123')

<_sre.SRE_Match object; span=(0, 11), match='192.168.111'>

>>> re.search(r'[aeiou]',' love FishC.com!')

<_sre.SRE_Match object; span=(2, 3), match='o'>

>>> re.search(r'[a-z]',' love FishC.com!')

<_sre.SRE_Match object; span=(1, 2), match='l'>

>>> re.search(r'[0-9]',' love FishC.com!')

>>> re.search(r'[aeiou]',' love 123 FishC.com!')

<_sre.SRE_Match object; span=(2, 3), match='o'>

>>> re.search(r'ab{3}c','abbbc')

<_sre.SRE_Match object; span=(0, 5), match='abbbc'>

>>> re.search(r'ab{3,10}c','abbbbbbbc')

<_sre.SRE_Match object; span=(0, 9), match='abbbbbbbc'>

>>> re.search(f'[01]\d\d|2[0-4]\d|25[0-5]','188')

SyntaxError: invalid syntax

>>> re.search(r'[01]\d\d|2[0-4]\d|25[0-5]','188')

<_sre.SRE_Match object; span=(0, 3), match='188'>

>>> re.search(r'(([01]{0,1}\d{0,1}\d|2[0-4]\d|25[0-5])\.){3}([01]{0,1}\d{0,1}\d|2[0-4]\d|25[0-5])','192.168.1.1')

<_sre.SRE_Match object; span=(0, 11), match='192.168.1.1'>

>>> 

2.第二部分

>>> re.search(r'fish(C|D)','FishhC')

>>> re.search(r'Fish(C|D)','FishhC')

>>> re.search(r'Fish(C|D)','FishC')

<_sre.SRE_Match object; span=(0, 5), match='FishC'>

>>> re.search(r'Fish(C|D)','FishD')

<_sre.SRE_Match object; span=(0, 5), match='FishD'>

>>> re.search(r'^FishC','I love FishC.com!')

>>> re.search(r'^FishC','FishC.com!')

<_sre.SRE_Match object; span=(0, 5), match='FishC'>

>>> re.search(r'FishC$','FishC.com')

>>> re.search(r'FishC$','love FishC)

SyntaxError: EOL while scanning string literal

>>> re.search(r'FishC$','love FishC')

<_sre.SRE_Match object; span=(5, 10), match='FishC'>

>>> re.search(r'(FishC)\1','FishC.com')

>>> re.search(r'(FishC)\1','FishCFishC)

SyntaxError: EOL while scanning string literal

>>> re.search(r'(FishC)\1','FishCFishC')

<_sre.SRE_Match object; span=(0, 10), match='FishCFishC'>

>>> re.search(r'[.]','FishC.com')

<_sre.SRE_Match object; span=(5, 6), match='.'>

>>> re.findall(r'[a-z]','FishC.com')

['i', 's', 'h', 'c', 'o', 'm']

>>> re.search(r'[^a-z]','FishC.com\n')

<_sre.SRE_Match object; span=(0, 1), match='F'>

>>> re.search(r'[a-z^]','FishC.com\n')

<_sre.SRE_Match object; span=(1, 2), match='i'>

>>> re.findall(r'[^a-z]','FishC.com\n')

['F', 'C', '.', '\n']

>>> re.search(r'FishC{3}','FishCCC')

<_sre.SRE_Match object; span=(0, 7), match='FishCCC'>

>>> re.search(r'(FishC){3}','FishCCC')

>>> re.search(r'(FishC){3}','FishCFishCFishC')

<_sre.SRE_Match object; span=(0, 15), match='FishCFishCFishC'>

>>> re.search(r'(FishC){13}','FishCFishCFishC')

>>> re.search(r'(FishC){1-3}','FishCFishCFishC')

>>> re.search(r'(FishC){1,3}','FishCFishCFishC')

<_sre.SRE_Match object; span=(0, 15), match='FishCFishCFishC'>

>>> s='I love FishC.com'

>>> re.search(r'<.+>',s)

<_sre.SRE_Match object; span=(0, 44), match='I love FishC.com'>

>>> re.search(r'<.+?>',s)

<_sre.SRE_Match object; span=(0, 6), match=''>