Python regular expression learning small example
Regular expressions are a powerful tool for processing strings. As a concept, regular expressions are not unique to Python. However, regular expressions in Python still have some subtle differences in actual use.
(1) Match the number between 1-100
import re
s ='100' # 1-Any number within 100
ret = re.match(r'(100|[1-9]\d{0,1})$',s)print(ret.group())
(100|[1- 9]\ d{0,1})$
100 Can match 100 | or match a number in [1-9], and then \d is a number, and the following {0,1} matches at most one number or no number
[1- 9]\ d means that it can only be any number with 1-9 in the front, mainly excluding 0, otherwise 01 is not allowed, and 0 is included in the back.
(2) Match landline number
010- 67132692 , Its construction rule is [3 digits][-][8 digits]
or
0516- 8978981 , Its construction rule is [4 digits][-][7 digits]
import re
s ="010-67132692"
ret = re.search(r'^\d{3,4}-\d{7,8}$', s)print(ret.group())
Note: print(ret.group(0)) has the same effect, python can be 0 by default, and it can be obtained without (). Generally, php and js start with \1
**(3) Match the entered qq number (qq matching rule: length is 5-10 digits, composed of pure numbers, and cannot start with 0.) **
import re
s ="1101111123"
ret = re.match(r'[1-9]\d{4,9}$', s)if ret != None:print(ret.group())else:print('Match failed!')
(4) Find how many af in the string
import re
s ="asdfjvjadsffvaadfkfasaffdsasdffadsafafsafdadsfaafd"
ret = re.findall(r'(af)', s)print(len(ret))
(5) The rule is to cut one or more times according to the space
import re
s ="zhangsan lisi wangwu"
res = re.compile(r'\s+')
ret = res.split(s)print(ret)
Effect picture:
(6) Use regular\cut
import re
s ="c:\abc\a.txt"
res = re.compile(r'\')
ret = res.split(s)print(ret)
Effect picture:
(7) Replace more than 5 consecutive numbers with #
import re
s ="wer8934605juo123wa89320571f"
res = re.compile(r'\d{5,}')
ret = res.sub('#', s)print(ret)
Effect picture:
(8) Take out all letters in the string
import re
s ="abDEe23dJfd343dPOddfe4CdD5ccv!23rr"
res = re.compile(r'[a-zA-Z]+')
ret = res.findall(s)print(ret)
Effect picture:
**(9) Find words ending in the letter e, ignoring case **
import re
s ='THREE people at HERE do some THING'
res = re.compile(r'\w+e\b', re.I) #\b is the boundary
ret = res.findall(s)print(ret)
Effect picture:
(10) Replace multiple repeated letters with &
import re
s ="cudddbhuuujdddcaa"
res = re.compile(r'([a-zA-Z])+')
ret = res.sub('&', s)print(ret)
Effect picture:
(11) Replace multiple repeated letters with one letter (for example, replace ddd with d)
import re
s ="cudddbhuuujddd"
res = re.compile(r'([a-zA-Z])+')
ret = res.sub(r'',s)print(ret)
Effect picture:
(12) Get words with a length of 3 letters
import re
s ="min tian jiu yao fang jia le ,da jia"
ret = re.findall(r'\b\w{3}\b', s)print(ret)
Effect picture:
(13) Turn the string into'I want to learn programming'
import re
s ="me...me...I need to..Want to...Want to...Learn to learn...study...Editing..Programming..Cheng.Cheng...Cheng...Cheng"
res = re.sub(r'\W+','', s)
ret = re.sub(r'(.)+',r'',res)print(ret)
Effect picture:
(14) Remove the div and b tags
Result: regularimport re
s ="<div class='a'Regular<span expression</span <b style='color:red'Exercise</b </div "
ret = re.sub(r'(</?div.*? |</?b.*? )','',s)print(ret)
Effect picture:
(15) Find strings with only 3 numbers in each line
import re
s ='''121fefe
3 qsqse2
ded6d32
aaaaa1a
1234 adc
'''
ret = re.findall(r'^\D*\d\D*\d\D*\d\D*$', s ,re.M)print(ret)
Effect picture:
The following is a supplement
Collect some commonly used python regular exercises
# Match out 0-Number between 99
print("---Match out 0-Number between 99---")
ret = re.match(r"^[1-9]?[0-9]$","77")print(ret.group())
# 8 Passwords up to 20 digits, can be small letters, numbers, underscores
print("---, 8 to 20 digits password, can be large and small English characters, numbers, underscores---")
ret = re.match("[\w_]{8,20}","1123dasf1")print(ret.group())
# Matches the email address of 163, and@There are 4 to 20 bits before the symbol, such as [email protected]
print("---Matches the email address of 163, and@There are 4 to 20 bits before the symbol, such as [email protected]")
ret = re.match("[\w_]{4,20}@163\.com","[email protected]")print(ret.group())print("---b---")
ret = re.match(r".*\b163\b","[email protected]")print(ret.group())
# Match 1-Number between 100
print("---Match 1-Number between 100---")
ret = re.match("[1-9]?\d$|100","100")print(ret.group())
# Match 163, 126, qq mailbox
print("---Match 163, 126, qq mailbox---")
ret = re.match("[\w_]{4,20}@(163|126|qq)\.com","[email protected]")print(ret.group())
# match<html hello world</html
print("---match<html hello world</html ---")
ret = re.match(r"<([a-zA-Z]*) .*</\1 ","<html hello world</html ")print(ret.group())
# The first:Match out<html <h1 www.itcast.cn</h1 </html
print("---The first:Match out<html <h1 www.qblank.cn</h1 </html ---")
ret = re.match(r"<(\w*) <(\w*) .*</\2 </\1 ","<html <h1 www.itcast.cn</h1 </html ")print(ret.group())
# The second:Match out<html <h1 www.qblank.cn</h1 </html
print("---The second:Match out<html <h1 www.qblank.cn</h1 </html ")
ret = re.match("<(?P<name1 \w*) <(?P<name2 \w*) .*</(?P=name2) </(?P=name1) ","<html <h1 www.qblank.cn</h1 </html ")print(ret.group())
# ******Advanced usage of re module*****
# Use search to match the number of readings of the article
print("---Number of reads of matching article---")
ret = re.search(r"\d+","The number of reads is 9999")print(ret.group())
# Statistics out python, c, c++The number of times the corresponding chapter was read
print("---Statistics out python, c, c++The number of times the corresponding chapter was read---")
ret = re.findall(r"\d+","python = 2342,c = 7980,java = 9999")print(ret)
# Add 1print to the number of matched readings("---Add 1 to the number of matched readings---")
ret = re.sub(r"\d+","999","python = 997")print(ret)
# < div
# < p Job responsibilities:</p
# < p Complete server-side related tasks such as recommendation algorithm, data statistics, connection, and background</p
# < p <br </p <p Required requirements:</p <p Good self-driven and professional quality, be proactive and result-oriented</p
# < p <br </p <p Technical requirements:</p
# < p 1. More than one year of Python development experience, master face-oriented object analysis and design, and understand design patterns</p
# < p 2. Master HTTP protocol, familiar with concepts such as MVC, MVVM and related WEB development frameworks</p
# < p 3. Master the development and design of relational database, master SQL, and use MySQL proficiently/One of PostgreSQL<br </p
# < p 4. Master NoSQL and MQ, and be proficient in using corresponding technologies to solve solutions</p
# < p 5. Familiar with Javascript/CSS/HTML5，JQuery、React、Vue.js</p
# < p <br </p <p bonus items:</p
# < p Large data, mathematical statistics, machine learning, sklearn, high performance, high concurrency.</p
# < /div
data ="""
< div
< p Job responsibilities:</p
< p Complete server-side related tasks such as recommendation algorithm, data statistics, connection, and background</p
< p <br </p <p Required requirements:</p <p Good self-driven and professional quality, be proactive and result-oriented</p <p <br </p <p Technical requirements:</p
< p 1. More than one year of Python development experience, master face-oriented object analysis and design, and understand design patterns</p
< p 2. Master HTTP protocol, familiar with concepts such as MVC, MVVM and related WEB development frameworks</p
< p 3. Master the development and design of relational database, master SQL, and use MySQL proficiently/One of PostgreSQL<br </p
< p 4. Master NoSQL and MQ, and be proficient in using corresponding technologies to solve solutions</p
< p 5. Familiar with Javascript/CSS/HTML5，JQuery、React、Vue.js</p
< p <br </p <p bonus items:</p
< p Large data, mathematical statistics, machine learning, sklearn, high performance, high concurrency.</p
< /div
"""
print("---Crawl employment information URL---")
# method one:Turn off greedy mode
print("---method one---")
ret = re.sub(r"<.+? ","",data)print(ret)
# Method Two:print("---Method Two---")
ret = re.sub(r"</?\w+ ","",data)print(ret)
# Cutting the string "info:xiaoZhang 33 shandong”
print("---Cutting the string "info:xiaoZhang 33 shandong”---")
ret = re.split(r":|","Cutting string info:xiaoZhang 33 shandong")print(ret)
# This is a number 234-235-22-423
data ="This is a number 234-235-22-423"print("---Greedy and non-greedy---")
# greedy
ret = re.match(".+(\d+-\d+-\d+-\d+)",data)print(ret.group(1))
# Non-greedy
ret = re.match(".+?(\d+-\d+-\d+-\d+)",data)print(ret.group(1))
# Extract the url of the picture
data ="""
< img data-original="https://rpic.douyucdn.cn/appCovers/2016/11/13/1213973_201611131917_small.jpg"
src="https://rpic.douyuc dn.cn/appCovers/2016/11/13/1213973_201611131917_small.jpg"
style="display:inline;""""
print("---Extract the url of the picture")
ret = re.search(r"https.+?\.jpg",data)print(ret.group())
data ="""
http://www.interoem.com/messageinfo.asp?id=35
http://3995503.com/class/class09/news_show.asp?id=14
http://lib.wzmc.edu.cn/news/onews.asp?id=769
http://www.zy-ls.com/alfx.asp?newsid=377&id=6
http://www.fincm.com/newslist.asp?id=415"""
# Remove the suffix
print("---Remove the suffix---")
ret = re.sub(r"(http://.+?/).*", lambda x: x.group(1),data)print(ret)
# Find all words
data ="hello world ha ha"print("---Find all words---")print("--method one--")
ret = re.split(r" +",data)print(ret)print("--Method Two--")
ret = re.findall(r"\b[a-zA-Z]+\b",data)print(ret)
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