Truthy and Falsy Values in Python – Conditional Logic Simplified

In Python, some values are treated as True or False automatically when used in conditions.

Falsy values (evaluated as False):

• None
• False
• 0 (any numeric zero)
• "" (empty string)
• [] (empty list)
• {} (empty dict)
• set() (empty set)

Everything else is truthy.

username = ""
 
if username:
    print("Welcome,", username)
else:
    print("Please enter a valid username")

Since username is an empty string (""), it's falsy — the else block runs.

✅ Quick Practice Example

score = 75
 
if score:
    if score >= 90:
        print("Grade A")
    elif score >= 75:
        print("Grade B")
    else:
        print("Grade C")
else:
    print("No score provided")