Python code to subtract a value but don't go below 0

Question

I need to subtract a value from a field and return that value to the new field, but if the value is below 0 simply return 0. I know I can do this with calculate field but I am unsure of how to write this in Python.

Example:

3200-1200=2000

800-1200=0

1211-1200=11

80-1200=0

Thanks for any help.

DavidSolari · Accepted Answer

As a one-line function:

def sub_to_zero(a, b): return a - b if a > b else 0

rzufelt · Accepted Answer

can use the max() function.

Takes the max value.  Since 0 is larger than any negative number, will return 0

R_