python基礎(chǔ)知識點(diǎn)講解

sudo apt-get install python-MySQLdb

import MySQLdb

conn = MySQLdb.connect(host="localhost",user="root",passwd="123456",db="test",charset="utf8")

cur = conn.cursor()

cur.execute("insert into users (username,password,email) values (%s,%s,%s)",("python","123456","python@gmail.com"))

cur.executemany("insert into users (username,password,email) values (%s,%s,%s)",(("google","111222","g@gmail.com"),("facebook","222333","f@face.book"),("github","333444","git@hub.com"),("docker","444555","doc@ker.com")))

conn.commit()

cur.execute("select * from users")

cur.execute("select * from users")
lines = cur.fetchall()
for line in lines:
 print line

cur.execute("select * from users where id=1")
line_first = cur.fetchone() #只返回一條
print line_first

cur.execute("select * from users")
print cur.fetchall()

cur.scroll(1)
cur.scroll(-2)
cur.scroll(2,"absolute") #回到序號是2,但指向第三條

cur.execute("update users set username=%s where id=2",("mypython"))
conn.commit()

conn = MySQLdb.connect("localhost","root","123456",port=3306,charset="utf8") #創(chuàng)建數(shù)據(jù)庫時(shí)不指定那個(gè)數(shù)據(jù)庫
conn.select_db("test") #連接創(chuàng)建后再指定

cur.close() #先關(guān)閉游標(biāo)
conn.close() #再關(guān)閉數(shù)據(jù)庫

class 類名：
 成員變量
 成員函數(shù)

class MyClass():
 first = 123
 def fun(self):
 print "I am function"

if __name__ == "__main__":
 myClass = MyClass() #創(chuàng)建類的一個(gè)實(shí)例

class Person:
 def __init__(self, name, lang, website):
 self.name = name
 self.lang = lang
 self.website = website

# 抽象形狀類
class Shape:
 # 類的屬性
 edge = 0
 # 構(gòu)造函數(shù)
 def __init__(self, edge):
 self.edge = edge
 # 類的方法
 def getEdge(self):
 return self.edge
 # 抽象方法 
 def getArea(self):
 pass

#三角形類，繼承抽象形狀類
class Triangle(Shape):
 width = 0
 height = 0
 # 構(gòu)造函數(shù)
 def __init__(self, width, height):
 #調(diào)用父類構(gòu)造函數(shù)
 Shape.__init__(self, 3)
 self.width = width
 self.height = height
 #重寫方法
 def getArea(self):
 return self.width * self.height / 2

#四邊形類，繼承抽象形狀類 
class Rectangle(Shape):
 width = 0
 height = 0
 # 構(gòu)造函數(shù)
 def __init__(self, width, height):
 #調(diào)用父類構(gòu)造函數(shù)
 Shape.__init__(self, 4)
 self.width = width
 self.height = height
 #重寫方法
 def getArea(self):
 return self.width * self.height

triangle = Triangle(4,5);
print triangle.getEdge()
print triangle.getArea()

rectangle = Rectangle(4,5);
print rectangle.getEdge()
print rectangle.getArea()