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I am writing a simple Python client and server, which works fine passing the server address within my code, however, I want the user to be able to enter the server address and throw and error if its incorrect. When I have the code below I get a error message from the terminal "list index out of range".
server = (sys.argv[1])
serverAdd = (server, '65652') # server address and port number
Can anyone help me with this please.
When I run my client program in python I want to be able to enter a address to connect to and store that in server. I run the program directly from the command line by typing programname.py. The server is already running listening for incoming connections.
369
To fix this, you can modify the parameter in the range() function. A better solution is to use the length of the list as the range() function's parameter. The code above runs without any error because the len() function returns 3. Using that with range(3) returns 0, 1, 2 which matches the number of items in a list.
To use, sys. argv in a Python script, we need to impo r t the sys module into the script. Like we import all modules, "import sys" does the job. Ideally, we want this at the top of the script, but anywhere before we use the sys.
You'll get the Indexerror: list index out of range error when you try and access an item using a value that is out of the index range of the list and does not exist. This is quite common when you try to access the last item of a list, or the first one if you're using negative indexing.
sys. argv is the list of commandline arguments passed to the Python program. argv represents all the items that come along via the command line input, it's basically an array holding the command line arguments of our program.
With this Python:
import sys
print(sys.argv)
And invoked with this command:
>python q15121717.py 127.0.0.1
I get this output:
['q15121717.py', '127.0.0.1']
I think you are not passing a argument to your Python script
Now you can change your code slightly to take a server form the command line or prompt for a server when none is passed. In this case you would look at something like this:
if len(sys.argv) > 1:
print(sys.argv[1])
else:
print(input("Enter address:"))
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