Python Forum

The problem:
We have a loud talking parrot. The "hour" parameter is the current hour time in the range 0..23. We are in trouble if the parrot is talking and the hour is before 7 or after 20. Return true if we are in trouble.

My code:

def parrot_trouble(talking, hour):
  if hour<7 or hour>20:
    return talking
  else:
    return False

Their solution:

def parrot_trouble(talking, hour):
  return (talking and (hour < 7 or hour > 20))

How does the simplified version work? I don't understand how the "and" works in that final return statement.

(May-31-2018, 04:18 AM)wlsa Wrote: [ -> ]We are in trouble if the parrot is talking and the hour is

This is not an alternate solution. In your function, there is not 'talking' in the if condition although it is in the assignment.

in their return statement they have two parts/conditions

• talking
  
• (hour < 7 or hour > 20)
  

python evaluates from left to right so if talking is evaluated to True it will evaluate the second condition because and requires all conditions to be True. It will stop evaluating at the moment when it is clear. i.e. if talking is False, it will return False, without evaluating the second condition at all.