How can I make python script show an error when user inputs same file name with this piece of code?-CodePudding

I was creating a note taking program, using the user voice command. When the file already exists, I want to show an error. It runs smoothly when the file name is different though. When the file already exists, I have coded to open in the writing mode. It would erase the earlier file, and write new instead of adding in the append mode.

elif 'note' in query:
            try:
                speak(" Okay master. what's the file name")
                b= takecommand()
                f = open(f"{b}.txt","w")
                speak("Okay master. tell me what to note down")
                a= takecommand()
                f.write(f"{a}\n")
                f.close()
            except Exception as e:
                speak("file name already exist")

Can you help me with troubleshooting the script? Like how could I first make it thrown an error when the filename is same?

CodePudding user response：

You'd want to check if the file exists after they input it, which can be done using "os.path.exists" as also suggested by Tim Roberts. Here's code that should work for you:

elif 'note' in query:
        try:
            Looper = True # Added a loop so it can repeatedly ask the user until they give a valid answer.
            speak(" Okay master. what's the file name") # Put here instead of in the loop so it will repeat once since the else condition already asks for a new file name aswell.
            while Looper == True:
                b = takecommand()
                if os.path.exists(f"{b}.txt"):
                    f = open(f"{b}.txt","w")
                    speak("Okay master. tell me what to note down")
                    a= takecommand()
                    f.write(f"{a}\n")
                    Looper = False # So the loop won't repeat again (regardless of the below line).
                    f.close()
                else:
                    speak("That file already exists. Give me a new file name.")
        except Exception as e:
            speak("Hm, an error occured. Try again later.")

I also added in a while loop for you, so that way if the user gives a file name that already exists, it will keep asking until they give a valid file name.

Ensure you have OS imported for the code to work by adding the following to the top of your code:

import os

CodePudding user response：

Use mode 'x'

x' create a new file and open it for writing. The 'x' mode implies 'w' and raises an FileExistsError if the file already exists.

try:
    # ...
    f = open(f"{b}.txt","x")
    # ...
except FileExistsError:
    speak("file name already exist")

Or mode 'a' to append the strings to existing file.

'a' open for writing, appending to the end of the file if it exists