Basic python and python tutorials

Basic python and python tutorials

Before getting the room number, we should first solve the bug left over from the previous article, that is, the entered room number is not a problem because the number does not exist and the corresponding room number does not exist.

The entered room number is not a number:

In python, What you enter must be a string. Although you enter a number, the type is str.

RoomId = input ('Enter the room number :')

Using the code in the previous article, let's test it.

In python, only the same type can be connected with "+", so the code in the previous article can be changed

roomUrl = 'http://live.bilibili.com/'+ roomId

Now we have expanded our knowledge to solve the problem. The powerful python has a string processing method. Now we only need to judge whether the entered character is a number. Call the isdigit () function to complete the requirement. I will sort out other string processing methods and post them to my blog.

Isdigit () meaning: If the string contains only numbers, True is returned; otherwise, False is returned.

After the judgment, the program will end. This is not what we want. What we need is an infinite judgment. If it is not a number, we need to return and re-enter it. If it is a number, we need to proceed to the next step.

Ideas:

1. Enter the room number.

2. Check whether the entered number is correct.

3. If it is a number, proceed to the next step; if it is not a number, re-enter it.

4. Judge after the input is complete, and then loop through it.

Code:

RoomId = input ('Enter the room number: ') while not roomId. isdigit (): print ("the number format is incorrect. Please enter it again! ") RoomId = input ('Enter the room number: ') roomUrl = 'HTTP: // live.bilibili.com/'+ str (roomId)

:

Check that the room number is empty and needs to be re-entered. The numbers and letters must be re-entered to meet our needs. We will continue to solve the next bug.

The entered room does not exist (that is, the website does not exist ):

This is a part of program exception handling. We only need to find out the cause of the program error.

In the last sentence, urllib. error. HTTPError: HTTP Error 404: Not Found.

Webpage 404, no webpage found. The webpage address you entered does not exist. Try-try t to solve this error.

Ideas:

1. Accessing a website does not know whether it is in

2. Try to access this address.

3. If an error occurs, enter the URL again.

4. re-enter the website address and start from entering the room number.

5. A large cycle starts with an error on the website. A small cycle is used to determine the room number.

6. If the entered URL exists, you need to jump out of this cycle.

Code:

While True: roomId = input ('Enter the room number: ') while not roomId. isdigit (): print ("the number format is incorrect. Please enter it again! ") RoomId = input ('Enter the room number: ') roomUrl = 'HTTP: // live.bilibili.com/'+ str (roomId) try: webPage = urllib. request. urlopen (roomUrl) break failed T: print ('error! ')

However, in this way, the user experience is not good, and we do not know where the error is, so we take the specific reason

Failed t urllib. error. HTTPError as reason: print ('URL error! '+ Str (reason ))

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