How to make decisions with if/else
Write a conditional
Python executes an if block only when its condition is truthy. A colon starts the block, and consistent indentation defines it.
temperature = 28
if temperature > 25:
print("It is warm")Add alternatives
elif checks another condition only if earlier branches failed. else handles everything remaining.
score = 82
if score >= 90:
grade = "A"
elif score >= 80:
grade = "B"
else:
grade = "C or below"
print(grade)Combine and chain comparisons
Use boolean operators for compound rules. Python also supports readable chained numeric comparisons.
age = 16
has_permission = True
if 13 <= age < 18 and has_permission:
print("Teen account allowed")Use conditional expressions sparingly
A conditional expression selects one of two values. It is concise for simple assignments but ordinary branches are clearer for multiple actions.
balance = 25
status = "positive" if balance >= 0 else "overdrawn"
print(status)