2016年5月 – 笨猪头的窝

作为练习python和tornado的一个小项目，要求输入网址，输出该网址的二维码

2. 安装纯python的二维码生成器模块qrcode，见官网最新qrcode 5.2.2

3. 编码实现：

第一步，简单的hello.html页面，允许输入网址并提交。

<html>
    <head><title>{{title}}</title></head>
<body>
    <form name="input" action="html_form_action" method="get">
        URL: <input type="text" name="URL" />
        <input type="submit" value="Submit" />
    </form>
</body>
</html>

<html>

<head><title>{{title}}</title></head>

<body>

URL: <input type="text" name="URL" />

</form>

</body>

</html>

第二步，简单的img.html页面，呈现生成的二维码

<html>
    <head><title>{{title}}</title></head>
    <body>
        <img src = {{imgName}} />
    </body>
</html>

<html>

<head><title>{{title}}</title></head>

<body>

</body>

</html>

第三步，功能实现部分，得到输入的网址，生成二维码，并输出到页面

import tornado.ioloop	 	
import tornado.web	 	
import qrcode	 	

class MainHandler(tornado.web.RequestHandler):	 	
	def get(self):	 	
		self.render("hello.html", title = "hellMickey")	 	

class FormHandler(tornado.web.RequestHandler):	 	
	def get(self):	 	
		url = self.get_argument("URL")	 	
		imgQR = qrcode.QRCode(version = 1, error_correction=qrcode.constants.ERROR_CORRECT_H, box_size = 10, border = 4,)	 	
		imgQR.add_data(url)	 	
		imgQR.make(fit=True)	 	
		img = imgQR.make_image()	 	
		img.save(url + '.png')	 	
		self.render("img.html", title = "QRCode", imgName = url + '.png')	 	

class ImgHandler(tornado.web.RequestHandler):	 	
	def get(self, path):	 	
		fileName = path + ".png"	 	
		try:	 	
			with open(fileName, 'rb') as f:	 	
				data = f.read()	 	
				self.write(data)	 	
			self.finish()	 	
		except IOError:	 	
			self.write("Error")	 

def make_app():	 	
	return tornado.web.Application([
		(r"/", MainHandler), (r"/html_form_action", FormHandler),(r"/(.*).png", ImgHandler),
		])	 	

if __name__ == "__main__":	 	
	app = make_app()	 	
	app.listen(8888)	 	
	tornado.ioloop.IOLoop.current().start()

import tornado.ioloop

import tornado.web

import qrcode

class MainHandler(tornado.web.RequestHandler):

def get(self):

self.render("hello.html", title = "hellMickey")

class FormHandler(tornado.web.RequestHandler):

def get(self):

url = self.get_argument("URL")

imgQR = qrcode.QRCode(version = 1, error_correction=qrcode.constants.ERROR_CORRECT_H, box_size = 10, border = 4,)

imgQR.add_data(url)

imgQR.make(fit=True)

img = imgQR.make_image()

img.save(url + '.png')

self.render("img.html", title = "QRCode", imgName = url + '.png')

class ImgHandler(tornado.web.RequestHandler):

def get(self, path):

fileName = path + ".png"

try:

with open(fileName, 'rb') as f:

data = f.read()

self.write(data)

self.finish()

except IOError:

self.write("Error")

def make_app():

return tornado.web.Application([

(r"/", MainHandler), (r"/html_form_action", FormHandler),(r"/(.*).png", ImgHandler),

])

if __name__ == "__main__":

app = make_app()

app.listen(8888)

tornado.ioloop.IOLoop.current().start()

今天下午，想重新温习下SQL，就刷了下LeetCode上有关Database的简单题和中等题。

简单题

1. Employees Earning More Than Their Managers

SELECT a.Name
FROM Employee a INNER JOIN Employee b ON a.ManagerId = b.Id
WHERE a.Salary > b.Salary

SELECT a.Name

FROM Employee a INNER JOIN Employee b ON a.ManagerId = b.Id

WHERE a.Salary > b.Salary

2. Duplicate Emails

SELECT Email
FROM Person
GROUP BY Email
HAVING COUNT(Email) > 1

SELECT Email

FROM Person

GROUP BY Email

HAVING COUNT(Email) > 1

3. Combine Two Tables

SELECT FirstName, LastName, City, State
FROM Person p LEFT JOIN Address a ON p.PersonId = a.PersonId

1 2	SELECT FirstName, LastName, City, State FROM Person p LEFT JOIN Address a ON p.PersonId = a.PersonId

4. Customers Who Never Order

SELECT Name AS Customers
FROM Customers
WHERE Id NOT IN (SELECT CustomerId
	FROM Orders)

SELECT Name AS Customers

FROM Customers

WHERE Id NOT IN (SELECT CustomerId

FROM Orders)

SELECT Name AS Customers
FROM Customers
WHERE NOT EXISTS (SELECT CustomerId
	FROM Orders
	WHERE Orders.CustomerId = Customers.Id)

SELECT Name AS Customers

FROM Customers

WHERE NOT EXISTS (SELECT CustomerId

FROM Orders

WHERE Orders.CustomerId = Customers.Id)

5. Rising Temperature

SELECT b.Id
FROM Weather a RIGHT JOIN Weather b ON DATEDIFF(b.Date, a.Date) = 1
WHERE a.Temperature < b.Temperature

SELECT b.Id

FROM Weather a RIGHT JOIN Weather b ON DATEDIFF(b.Date, a.Date) = 1

WHERE a.Temperature < b.Temperature

SELECT b.Id
FROM Weather a RIGHT JOIN Weather b ON TO_DAYS(b.Date) - TO_DAYS(a.Date) = 1
WHERE a.Temperature < b.Temperature

SELECT b.Id

FROM Weather a RIGHT JOIN Weather b ON TO_DAYS(b.Date) - TO_DAYS(a.Date) = 1

WHERE a.Temperature < b.Temperature

SELECT b.Id
FROM Weather a RIGHT JOIN Weather b ON DATE_SUB(a.Date, INTERVAL -1 DAY) = b.Date
WHERE a.Temperature < b.Temperature

SELECT b.Id

FROM Weather a RIGHT JOIN Weather b ON DATE_SUB(a.Date, INTERVAL -1 DAY) = b.Date

WHERE a.Temperature < b.Temperature

6. Second Highest Salary

SELECT IFNULL((
		SELECT DISTINCT Salary AS SecondHighestSalary
		FROM Employee
		ORDER BY Salary DESC
		LIMIT 1, 1
		), NULL)

SELECT IFNULL((

SELECT DISTINCT Salary AS SecondHighestSalary

FROM Employee

ORDER BY Salary DESC

LIMIT 1, 1

), NULL)

SELECT (
                SELECT DISTINCT Salary
		FROM Employee
		ORDER BY Salary DESC
		LIMIT 1, 1
		) AS SecondHighestSalary

SELECT (

SELECT DISTINCT Salary

FROM Employee

ORDER BY Salary DESC

LIMIT 1, 1

) AS SecondHighestSalary

SELECT (
		SELECT DISTINCT Salary
		FROM Employee
		ORDER BY Salary DESC
		LIMIT 1 OFFSET 1
		) AS SecondHighestSalary

SELECT (

SELECT DISTINCT Salary

FROM Employee

ORDER BY Salary DESC

LIMIT 1 OFFSET 1

) AS SecondHighestSalary

7. Delete Duplicate Emails

DELETE FROM Person
WHERE Id NOT IN (SELECT Id
	FROM (SELECT MIN(Id) AS Id
		FROM Person
		GROUP BY Email
		) t)

DELETE FROM Person

WHERE Id NOT IN (SELECT Id

FROM (SELECT MIN(Id) AS Id

FROM Person

GROUP BY Email

) t)

中等题

8. Consecutive Numbers

SELECT DISTINCT l1.num
FROM Logs l1 JOIN Logs l2 ON l1.id = l2.id - 1 JOIN Logs l3 ON l1.id = l3.id - 2
WHERE l1.num = l2.num
	AND l2.num = l3.num

SELECT DISTINCT l1.num

FROM Logs l1 JOIN Logs l2 ON l1.id = l2.id - 1 JOIN Logs l3 ON l1.id = l3.id - 2

WHERE l1.num = l2.num

AND l2.num = l3.num

9. Rank Scores

SELECT Score, (
		SELECT COUNT(DISTINCT Score)
		FROM Scores
		WHERE Score >= s.Score
		) AS Rank
FROM Scores s
ORDER BY Score DESC

SELECT Score, (

SELECT COUNT(DISTINCT Score)

FROM Scores

WHERE Score >= s.Score

) AS Rank

FROM Scores s

ORDER BY Score DESC

10. Department Highest Salary

SELECT D.Name AS Department, E.Name AS Employee, E.Salary
FROM Employee E, (SELECT DepartmentId, MAX(Salary) AS max
	FROM Employee
	GROUP BY DepartmentId
	) T, Department D
WHERE E.DepartmentId = T.DepartmentId
	AND E.Salary = T.max
	AND E.DepartmentId = D.id

SELECT D.Name AS Department, E.Name AS Employee, E.Salary

FROM Employee E, (SELECT DepartmentId, MAX(Salary) AS max

FROM Employee

GROUP BY DepartmentId

) T, Department D

WHERE E.DepartmentId = T.DepartmentId

AND E.Salary = T.max

AND E.DepartmentId = D.id

11. Nth Highest Salary

CREATE FUNCTION getNthHighestSalary(N INT) RETURNS INT
BEGIN
DECLARE M INT;
SET M = N-1;
RETURN (
select IFNULL((select distinct Salary from Employee order by Salary DESC limit M, 1), null)
);
END

CREATE FUNCTION getNthHighestSalary(N INT) RETURNS INT

BEGIN

DECLARE M INT;

SET M = N-1;

RETURN (

select IFNULL((select distinct Salary from Employee order by Salary DESC limit M, 1), null)

);

END

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月份：2016年5月

输入网址，输出二维码(python + tornado)

LeetCode OJ_Database 简单题和中等题