How can I implement a function that increments file names when receiving them?

Question

How can I write a function that makes an increment name with the incoming files?

def callback(ch,method, properties, body):

    Payload = body.decode("utf-8")
    Payload = ast.literal_eval(Payload)

    with open("received.png", "wb") as f:
        f.write(Payload)

    print(type(Payload))
    print("Data Received : {}".format(Payload))

Here I receive an image.png and name it received.png. I want to write a function that automatically renames the next incoming image something like received_2.png

Create a global variable and increment it everytime function call. — Epsi95, Jan 09 '21 at 18:31
@Epsi95 "use a global variable" is the wrong answer 99% of the time — DeepSpace, Jan 09 '21 at 18:33
You receive bytes of an image and you use `literal_eval` ? Why so ? — azro, Jan 09 '21 at 18:34
@DeepSpace why? Can you elaborate? I am assuming that the increment will happen if I can save successfully, otherwise I will decrement. Where is the problem? — Epsi95, Jan 09 '21 at 18:39
@Epsi95 There is endless information on the web why global variables are a bad idea, look it up. — DeepSpace, Jan 09 '21 at 18:40

score 0 · Answer 1 · answered Jan 09 '21 at 18:34

0

You can get number of files in the current directory and add 1 to it. Here is code to get number of files in current dir

import os, os.path

print(len([name for name in os.listdir('.') if os.path.isfile(name)]))

answered Jan 09 '21 at 18:34

Franciszek Job

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2
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This is a very bad idea if there are thousands of files. – Epsi95 Jan 09 '21 at 18:47
Considering he has a special directory to store output files - its an good ideas. – Franciszek Job Jan 09 '21 at 18:52

How can I implement a function that increments file names when receiving them?

1 Answers1