re — Regular expression operations

import re
m = re.search('(?<=abc)def', 'abcdef')
m.group(0)
#'def'

JSON encoder and decoder

https://docs.python.org/3/library/json.html

urllib

#AU Crawler
import re
import urllib.request
import html2text
with urllib.request.urlopen('http://www.asia.edu.tw/news1.php') as response:
    html = response.read().decode('utf-8')
    pattern = '<font color="#446666" face="微軟正黑體" size="2">'
    for pos in re.finditer(pattern, html):
        pos2 = html.find('</font>', pos.end())
        sub = html[pos.end():pos2]
        print(sub)

CSV

https://docs.python.org/3/library/csv.html

#Write CSV
import csv
with open('names.csv', 'w', newline='') as csvfile:
    fieldnames = ['first_name', 'last_name']
    writer = csv.DictWriter(csvfile, fieldnames=fieldnames)

    writer.writeheader()
    writer.writerow({'first_name': 'Baked', 'last_name': 'Beans'})
    writer.writerow({'first_name': 'Lovely', 'last_name': 'Spam'})
    writer.writerow({'first_name': 'Wonderful', 'last_name': 'Spam'})
#Read CSV    
import csv
with open('names.csv', newline='') as csvfile:
  reader = csv.DictReader(csvfile)
  for row in reader:
      print(row['first_name'], row['last_name'])

shutil-— High-level file operations

from shutil import copyfile

from shutil import copyfile
copyfile(src, dst)

SQLite

sqlite3-DB-API 2.0 interface for SQLite databases https://docs.python.org/2/library/sqlite3.html

copyfile(src, dst)

A minimal SQLite shell for experiments

#Inserting data
import sqlite3 as lite
import sys

con = lite.connect('test.db')

with con:
    cur = con.cursor()    
    cur.execute("CREATE TABLE Cars(Id INT, Name TEXT, Price INT)")
    cur.execute("INSERT INTO Cars VALUES(1,'Audi',52642)")
    cur.execute("INSERT INTO Cars VALUES(2,'Mercedes',57127)")
    cur.execute("INSERT INTO Cars VALUES(3,'Skoda',9000)")
    cur.execute("INSERT INTO Cars VALUES(4,'Volvo',29000)")
    cur.execute("INSERT INTO Cars VALUES(5,'Bentley',350000)")
    cur.execute("INSERT INTO Cars VALUES(6,'Citroen',21000)")
    cur.execute("INSERT INTO Cars VALUES(7,'Hummer',41400)")
    cur.execute("INSERT INTO Cars VALUES(8,'Volkswagen',21600)")

#Retrieving data
import sqlite3 as lite
import sys
con = lite.connect('test.db')
with con:    
    cur = con.cursor()    
    cur.execute("SELECT * FROM Cars")
    rows = cur.fetchall()
    for row in rows:
        print (row)