python 大杂烩 合集
Installing MySQL for Python 3
sudo apt-get install build-essential python3-dev libmysqlclient-dev
sudo apt-get install python3-pip
**install the MySQL connector
using pip:**
sudo pip3 install mysql-connectoror
sudo apt-get install python3-mysql.connector
demo_mysql_connection.py:
import mysql.connector
mydb = mysql.connector.connect(
host="localhost",
user="yourusername",
password="yourpassword"
)
print(mydb)
Creating a Database
To create a database in MySQL, use the "CREATE DATABASE" statement:
import mysql.connector
mydb = mysql.connector.connect(
host="localhost",
user="yourusername",
password="yourpassword"
)
mycursor = mydb.cursor()
mycursor.execute("CREATE DATABASE mydatabase")
Creating a Table
import mysql.connector
mydb = mysql.connector.connect(
host="localhost",
user="yourusername",
password="yourpassword",
database="mydatabase"
)
mycursor = mydb.cursor()
mycursor.execute("CREATE TABLE customers (name VARCHAR(255), address VARCHAR(255))")
Insert Into Table
import mysql.connector
mydb = mysql.connector.connect(
host="localhost",
user="yourusername",
password="yourpassword",
database="mydatabase"
)
mycursor = mydb.cursor()
sql = "INSERT INTO customers (name, address) VALUES (%s, %s)"
val = ("John", "Highway 21")
mycursor.execute(sql, val)
mydb.commit()
print(mycursor.rowcount, "record inserted.")
Select From a Table
import mysql.connector
mydb = mysql.connector.connect(
host="localhost",
user="yourusername",
password="yourpassword",
database="mydatabase"
)
mycursor = mydb.cursor()
mycursor.execute("SELECT * FROM customers")
myresult = mycursor.fetchall()
for x in myresult:
print(x)
Python 使用 MySQLdb
檢查是否有安裝 MySQLdb 模組
python -c "import MySQLdb"
ImportError: No module named MySQLdb
MySQLdb 只支持python2，不支持python3
python mysql db 全局变量
global conn
conn = mysql.connector.connect(
host="localhost",
user="yourusername",
password="yourpassword"
)
python html parse
from html.parser import HTMLParser
class MyHTMLParser(HTMLParser):
def handle_starttag(self, tag, attrs):
print("Encountered a start tag:", tag, type(tag))
for attr in attrs:
# print(" attr:", attr, type(attr))
if(tag == "a" and attr[0] == 'href'):
print("href = ", attr[1])
def handle_endtag(self, tag):
print("Encountered an end tag :", tag)
def handle_data(self, data):
print("Encountered some data :", data)
parser = MyHTMLParser()
parser.feed('<html><head><title>Test</title></head>'
'<body><h1>Parse me!</h1><a href="https://www.baidu.com/">baidu</a></body></html>')
python file read
try:
f = open(filebat)
except FileNotFoundError:
print("file not found :", filebat)
else:
strfile = f.read()
python bytes to string
>>> b"abcde"
b'abcde'
# utf-8 is used here because it is a very common encoding, but you
# need to use the encoding your data is actually in.
>>> b"abcde".decode("utf-8")
'abcde'
python encoding
import os
import sys
ch = '中国'
print('GBK:', ch.encode('gbk'))
print('UTF8:', ch.encode('utf8'))
print('GBK:', ch.encode('gbk').decode('gbk'))
print('UTF8:', ch.encode('utf8').decode('utf8'))
GBK: b'xd6xd0xb9xfa'
UTF8: b'xe4xb8xadxe5x9bxbd'
GBK: 中国
UTF8: 中国
python tcp socket
import socket
socket.setdefaulttimeout(2)
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
try:
s.connect(("127.0.0.1", 5000))
except Exception as e:
print( str(e))
exit(0)
s.send(b'GET / HTTP/1.1\r\n\r\n')
while True:
data = s.recv(1024)
if data:
print(data.decode("utf8"))
else:
break
输出：
HTTP/1.0 200 OK
Content-Type: text/html; charset=utf-8
Content-Length: 10
Server: Werkzeug/2.0.3 Python/3.8.10
Date: Wed, 09 Mar 2022 01:46:40 GMT
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安装bluetooth
sudo apt-get update
sudo apt-get install python-pip python-dev ipython
sudo apt-get install bluetooth libbluetooth-dev
sudo pip install pybluez
python3 requests post octet-stream
import requests
with open('./x.png', 'rb') as f:
data = f.read()
res = requests.post(url='http://httpbin.org/post',
data=data,
headers={'Content-Type': 'application/octet-stream'})
python 实现sm3计算hash
p1 = subprocess.Popen(["echo", "-n", str], stdout=subprocess.PIPE)
p2 = subprocess.Popen(["openssl", "dgst", "-sm3"], stdin=p1.stdout, stdout=subprocess.PIPE)
sm3 = p2.stdout.readline()[9:-1]
print('sm3 = ', sm3)
python hex string to string
a = 'aabbccddeeff'
a_bytes = bytes.fromhex(a)
print(a_bytes)
b'\xaa\xbb\xcc\xdd\xee\xff'
aa = a_bytes.hex()
print(aa)
aabbccddeeff
python3 read file line by line
file1 = open('myfile.txt', 'r')
Lines = file1.readlines()
count = 0
for line in Lines:
count += 1
print("Line{}: {}".format(count, line.strip()))
python3 ubuntu beep
import os
import time
duration = 1 # seconds
freq = 440 # Hz
bool1 = True
elapsed_time = 0
while bool1:
start = time.time()
elapsed_time += time.time() - start
if elapsed_time >= 2.5:#Adjust yourself
os.system('play -nq -t alsa synth {} sine {}'.format(duration, freq))
bool1 = False