table of Contents
re module
It used to find specific things from a string (text) in
1. yuan characters: characters have special meaning
- ^ From the beginning of the match
import re
a = re.findall('^abc', 'abcsds')
b = re.findall('^abc', 'aabcsds') # 不是以abc开头，所以返回空
print(a,b)['abc'] []- $ Matches from the end
a = re.findall('abc$', 'sdfabcsdsabc')
b = re.findall('abc$', 'aabcsdsbc') # 不是以abc结尾，所以返回空
print(a,b)['abc'] []- | Or equivalent or
a = re.findall('a|bc', 'sdfabbcsdsabc') # 将匹配到的对象用列表的形式返回
print(a)['a', 'bc', 'a', 'bc']- [] Find the elements [] in the
a = re.findall('[bac]', 'sdfabcsdsabc')
print(a)['a', 'b', 'c', 'a', 'b', 'c']- [^] Negated, in addition to the match [^] inside the character, ^ metacharacter if written character set is anti-take
a = re.findall('[^bac]', 'sdfabcsdsabc')
print(a)['s', 'd', 'f', 's', 'd', 's']- After () Results match is found, take only, packet matches (in)
a = re.findall('a(bc)s', 'sdfabcsdsabc')
print(a)['bc']- Indicates any one character
a = re.findall('b.', 'sdb，sdb sdkjfbasd sdb') # 可表示任意字符，包括空格及其他字符
print(a)['b，', 'b ', 'ba']- {N} the front braces first character matches the most recent n times
a = re.findall('ab{3}','abbbbsfsabbs dfbbb')
print(a)['abbb']- * Character match in front of a 0 to infinity
a = re.findall('sa*','fsa dsaasdf')
print(a)['sa', 'saa', 's']- + 1 to the previous character to match an infinite number
a = re.findall('a+','fsa dsaasdf') # 至少要匹配到一个a
print(a)['a', 'aa']- ? Matches the preceding character zero or one
a = re.findall('sa?','fsa dsaasdf') # 匹配0或一个a
print(a)['sa', 'sa', 's']2. predefined characters: backslash behind the realization of special functions with ordinary characters
- \ D match numbers (0-9)
a = re.findall('\d', 'sda123jf 342 4sdf4')
print(a)['1', '2', '3', '3', '4', '2', '4', '4']- \ D matches non-numeric characters
a = re.findall('\D', 'sda123jf 342 4sdf4')
print(a)['s', 'd', 'a', 'j', 'f', ' ', ' ', 's', 'd', 'f']- \ S matches the null character
a = re.findall('\s', 'sda123jf 342 4sd,f4')
print(a)[' ', ' ']- \ S matches non-null character
a = re.findall('\S', 'sda123jf 342 4sd,f4')
print(a)['s', 'd', 'a', '1', '2', '3', 'j', 'f', '3', '4', '2', '4', 's', 'd', ',', 'f', '4']- \ W match letters, numbers, underscores
a = re.findall('\w', 'sd_f 34?2 4sd,f4')
print(a)['s', 'd', '_', 'f', '3', '4', '2', '4', 's', 'd', 'f', '4']- \ W matches non-alphabetic, non-numeric, non-underscore character
a = re.findall('\W', 'sd_f 34?2 4sd,f4')
print(a)[' ', '?', ' ', ',']3. Greed match: been looking until not satisfied
a = re.findall('a.*', 'asda123456asa')
print(a)['asda123456asa']4. Non-greedy match, find a stop,? Stop character equivalent
a = re.findall('a.*?', 'asda123456asa')
print(a)['a', 'a', 'a', 'a']The common features function
- re.complie the equivalent of writing a general rule template
phone_compile = re.compile('1\d{10}')
email_compile = re.compile('\w+@\w+.\w+')
test_s = '12345678900 [email protected] [email protected]'
res = phone_compile.findall(test_s)
print(res)
res = email_compile.findall(test_s)
print(res)['12345678900']
['[email protected]', '[email protected]']- re.match match from the beginning, to get a matching
a = re.match('\d','sdf123sdd456')
b = re.match('\d','123sdfa 212d')
print(a)
print(b)None
<_sre.SRE_Match object; span=(0, 1), match='1'>- re.search search to match the first character, and returns its index
a = re.search('\d','sdfs1213hfjsf 2323')
print(a)<_sre.SRE_Match object; span=(4, 5), match='1'>The difference between match and search: mathch to find a match from the beginning, search to find the first search all
- re, split according to a regular division matching string, it returns a list of the divided
s = 'asb sfsl sfjwo212 12312,dsfsf'
print(s.split(' '))
res = re.split('\d+',s)
print(res)['asb', 'sfsl', 'sfjwo212', '12312,dsfsf']
['asb sfsl sfjwo', ' ', ',dsfsf']- re, sub and two re.subn they are to replace the contents, but subn calculates how many times replaced, replace the built-in string methods similar to
import re
s = 'asfhf12fdgds 743wiuw22'
print(re.sub('\d',',',s))
print(re.subn('\d',',',s)) # 除了会修改内容，还会返回修改了多少次asfhf,,fdgds ,,,wiuw,,
('asfhf,,fdgds ,,,wiuw,,', 7)typing module
1. type checking, appeared parameters and return values type does not match the run-time.
2. incoming parameters and return types as development documents annotated, user-friendly call.
3. After adding the module does not affect the operation of the program, will not officially reported errors, only a reminder.
- Note: typing module can only be used in more than python3.5 version, pycharm currently supports typing inspection
from typing import List, Tuple, Dict
def add(a: int, string: str, f: float,
b: bool) -> Tuple[List, Tuple, Dict, bool]:
list1 = list(range(a))
tup = (string, string, string)
d = {"a": f}
bl = b
return list1, tup, d, bl
print(add(5, "hhhh", 2.3, False))Crawling Audio
import re
import requests
response = requests.get('http://www.gov.cn/premier/index.htm')
data = response.text
res = re.findall('href="(/\w+/\w+_yp.htm)"', data) # ()只取括号内的
yp_res = 'http://www.gov.cn' + res[0]
yp_response = requests.get(yp_res)
yp_data = yp_response.text
res = re.findall('<a href="(.*?)"', yp_data)
count = 0
for url in res:
if url == 'javascript:;':
continue
mp3_url = 'http://www.gov.cn' + url
mp3_response = requests.get(mp3_url)
mp3_response.encoding = 'utf8' # 改变网址的utf8
mp3_data = mp3_response.text
# print(mp3_data)
res = re.findall('<title>(.*?)</title>|data-src="(.*?)"',mp3_data)
title = res[0][0]
mp3_url = res[1][1]
if res[1][1].startswith('/home'):
continue
res_response = requests.get(mp3_url)
mp3_data = res_response.content # MP3的二进制形式
with open(f'{title}.mp3','wb') as fw:
fw.write(mp3_data)
fw.flush()
count += 1
print(f'{count}')