🐍 If else
Good to know
⭐️ All non-zero numbers, non-empty strings, lists, dicts, etc. evaluate as True.
Basic If Statement
Runs only if the condition is True.
age = 20
if age >= 18:
print("Adult")If / Else
Two possible branches.
age = 15
if age >= 18:
print("Adult")
else:
print("Minor")If / Elif / Else
Check multiple exclusive conditions.
temp = 25
if temp > 30:
print("Hot")
elif temp > 20:
print("Warm")
elif temp > 10:
print("Cool")
else:
print("Cold")Nested If Statements
Useful but can become messy — prefer combining conditions when possible.
user = "Admin"
logged_in = True
if logged_in:
if user == "Admin":
print("Welcome Admin!")Combining Conditions (and / or / not)
Use logical operators to make cleaner conditions.
age = 22
has_ticket = True
if age >= 18 and has_ticket: # Also possible: or / not
print("Entry allowed")If in
List
if "cat" in ["dog", "cat", "mouse"]:
print("Found the cat!")Strings
if "he" in "hello":
print("Substring found!")Dict keys
person = {"name": "Alain", "age": 30}
if "name" in person:
print("Key exists")Dict values
Unless you ask explicitly:
if "Alain" in person.values():
print("Value exists")Opposite: not in
if "banana" not in ["apple", "cherry"]:
print("Banana missing")Truthy and Falsy Values
Python evaluates these as False:
# 0
# "" (empty string)
# [], {}, () (empty containers)
# None
name = ""
if not name:
print("Name is missing")Ternary Expression (Short If-Else)
Good for small inline choices.
age = 17
status = "Adult" if age >= 18 else "Minor"
print(status)