arguments - Python Error: "ValueError: need more than 1 value to unpack"

Question

In Python, when I run this code:

from sys import argv

script, user_name =argv
prompt = '>'

print "Hi %s, I'm the %s script." % (user_name, script)

I get this error:

Traceback (most recent call last):  
script, user_name =argv  
ValueError: need more than 1 value to unpack

What does that error mean?

Answer 1

Probably you didn't provide an argument on the command line. In that case, sys.argv only contains one value, but it would have to have two in order to provide values for both user_name and script.