module random

module random

1. random.random() [0,1) 内的float pseudo randomizer

2. random.sample() sample(population,k) method of random.Random instance,choose k unique random elements from a population sequence or set,returns a new list

3. random.uniform() [a,b] or [a,b) depending on rounding

4. random.randint()

5. random.shuffle()

module collections

1. namedtumple

from collections import namedtuple
​
Rectangle=namedtuple('Rectangle_class',('length','width'))
vv=Rectangle(11,13)
print(vv.length,vv.width)
print(vv[0],vv[1])

2. defaultdict

from collections  import defaultdict
v=defaultdict(int,name='bud',age=29)
print(v)
print(v['addr'])
print(v['bow'])
print(v)
def c():
    return 'vvvvv'
bb=defaultdict(lambda :'bbb',name='bud',age=22)
print(bb['addr'])
print(bb['bow'])
print(bb)

3.Counter

from collections import Counter
bb='zxczxcvbnadas'
print(Counter(bb))
print(Counter(bb).most_common(3))

module re

quantifier

• {n}

• {n,}

• {n,m}

• ?

• +

• *

• 使用quantifier注意界定范围,经常和()连用

metacharacter

\d      [0-9]       digit
\D      [^\d] [^0-9]        non-digit
\w      [0-9A-Za-z]
\W      [^\w] [^0-9A-Za-z]
\s      [ \t\n]
\S      [^ \t\n]
\t      tab
\n
[]
[^]
^       $
|
()

 

 

 

matching decimal

1. \d+(\.\d+)?

2. greedy match & back-track algorithm

   \d{3,}6

   non-greedy match

   \d{3,}?6 ? follows quntifier

   1\d??3

   133 -> 13 在133这种情况下优先选择13进行匹配

• .*?X 遇到X就停

• .*X 最后一个X停止

• [1-9]\d{14}(\d{2}[\dx])?

• ^([1-9]\d{14}|[1-9]\d{16}[\dx])$

取整数

import re
ret=re.findall(r"\d+\.\d+|(\d+)","1-2*(60+(-40.35/5)-(-4*3))")
print(ret)
ret=filter(lambda v:v,ret)
# ret=[v for v in ret if v]
print(list(ret))

分组命名

import re
exp='<br>flasvlxcv</br>fasdf</a>'
bud=re.search(r'<(?P<tag>\w+)>(.*?)</(?P=tag)>',exp)
print(bud)
print(bud.group())
bow=re.search('<(\w+)>(.*?)</\\1>',exp)
print(bow)

(?P<name>regex) (?P=name)

re.split

import re
dip=re.split('\d+',"eva345egon456yuan")
print(dip)
print(re.split('(\d+)',"eva345egon456yuan"))
print(re.split('\d(\d)\d',"eva345egon456yuan"))
print(re.split('\d(\d)\d',"eva345egon456yuan",1))

import re
dip=re.findall(r'www.(bai|jd).com','www.jd.com')
print(dip)
print(re.split('[ab]','afasmb234'))
print(re.sub('\d','&','eva3egon4yuan4',2))
print(re.subn('\d','$','eva3egon4yuan4',1))
dim=re.compile('\d{3}')
print(dim.search('abc123eeee').group())
dye=re.finditer('\d','ds3sy4784a')
print(dye)
print(dye.__next__)
print(dye.__next__())
print(next(dye))
for v in dye:
    print(v.group())

import re
dip=re.compile('\d+')
print(dip.findall('zxc23423vxcvxc354'))
print(dip.search('zxc23423vxcvxc354'))
​
dim=re.finditer('\d+','zx123bvdf234df23')
print('__iter__' in dir(dim) and '__next__' in dir(dim))
# for v in dim:
#     print(v)
for v in dim:
    print(v.group())

reptile

import json,re,requests
headers={'User-Agent': 'Mozilla/5.0 (Windows NT 6.1; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/79.0.3945.88 Safari/537.36'}
def getPage(vv):
    print(vv)
    response=requests.get(vv,headers=headers)
    print(response,type(response))
    return response.text
​
def parsePage(vv):
    # print(vv)
    dip=re.compile('<div class="item">.*?<div class="pic">.*?<em .*?>(?P<id>\d+).*?<span class="title">\
(?P<title>.*?)</span>.*?<span class="rating_num".*?>(?P<rating_num>.*?)\
</span>.*?<span>(?P<comment_num>.*?)</span>',re.S)
    dim=dip.finditer(vv)
    for bb in dim:
        yield {
            'id':bb.group('id'),
            'title':bb.group('title'),
            'rating_num':bb.group('rating_num'),
            'comment_num':bb.group('comment_num'),
        }
​
def main(num):
    url='https://movie.douban.com/top250?start=%s&filter=' % num
    # print(url)
    response_html=getPage(url)
    # print(reponse_html)
    bow=parsePage(response_html)
    print(bow)
    f=open('vv',encoding='utf-8',mode='wt')
    for xx in bow:
        print(xx,type(xx))
        data=json.dumps(xx,ensure_ascii=False)
        print(type(data),xx==data)
        f.write(data+'\n')
​
if __name__ == '__main__':
    count=0
    for x in range(10):
        main(count)
        count+=25