Python Glossary: 10 Core Terms with Examples

Review ten Python fundamentals with short examples. Change a value and predict the output before running the code. Examples use Python 3.

Studio01 · 2026-10-24

Variable

A name bound to a value so you can refer to it later. Assignment in Python does not permanently fix the variable's type.

count = 2
count = count + 1
print(count)  # 3

A type for text. An f-string makes it easy to insert a value into a readable message.

name = "Mika"
print(f"Hello, {name}!")  # Hello, Mika!

An ordered collection you can change. Use a list when items need to be added, removed, or replaced.

scores = [7, 9]
scores.append(8)
print(scores)  # [7, 9, 8]

An ordered collection whose item references cannot be replaced. A tuple may still contain mutable objects.

point = (3, 5)
x, y = point
print(x + y)  # 8

A mapping from unique, hashable keys to values. Look up a value by its key.

book = {'title': 'Python', 'pages': 120}
print(book['pages'])  # 120

A collection of distinct, hashable elements. Useful for removing duplicates and checking membership; iteration order is not guaranteed.

tags = {'python', 'books', 'python'}
print(len(tags))  # 2
print('books' in tags)  # True

Visits items from an iterable one at a time. The end of a range is excluded.

for number in range(1, 4):
    print(number)  # 1, then 2, then 3

A reusable block defined with def. Parameters accept inputs; return sends a result to the caller.

def double(value):
    return value * 2

print(double(6))  # 12

True or False represents whether a condition holds. A comparison expression can be used in an if statement.

has_book = True
if has_book:
    print("Start reading")

An error raised while code runs. Use try/except to handle a failure you can anticipate; avoid silently swallowing overly broad exceptions.

try:
    pages = int("120")
except ValueError:
    print("Could not convert to a number")
else:
    print(pages)  # 120