One-liner Python code for setting string to 0 string if empty

Question

What is a one-liner code for setting a string in python to the string, 0 if the string is empty?

# line_parts[0] can be empty
# if so, set a to the string, 0
# one-liner solution should be part of the following line of code if possible
a = line_parts[0] ...

Answer 1

a = '0' if not line_parts[0] else line_parts[0]

Answer 2

a = line_parts[0] or "0"

This is one of the nicest Python idioms, making it easy to provide default values. It's often used like this for default values of functions:

def fn(arg1, arg2=None):
    arg2 = arg2 or ["weird default value"]

Answer 3

Do you mean string is empty(means string of length zero) or None ?