Python any() and all() Examples

Short, runnable programs that show python any() and all() in action. Read the explanation, press Run, then change the code and try your own ideas. New to the topic? Start with the Python any() and all() lesson.

1Blocking comments with banned words

any() replaces a long chain of or tests. Lowercasing the comment first makes the match case-insensitive.

Blocking comments with banned words

banned = ["spam", "scam", "free money"]
comments = ["Great lesson, thanks!", "Get FREE MONEY now", "This is a scam"]

for comment in comments:
    text = comment.lower()
    flagged = any(word in text for word in banned)
    print("blocked" if flagged else "ok", "-", comment)

Expected outputok - Great lesson, thanks!
blocked - Get FREE MONEY now
blocked - This is a scam

2Checking a tic-tac-toe board with nested any and all

all() asks whether every cell of a line holds an X, and the outer any() asks whether any row or column is such a line. Combining the two is natural once each reads as a sentence.

Checking a tic-tac-toe board with nested any and all

board = [
    ["X", "O", "X"],
    ["O", "X", "X"],
    ["O", "O", "X"],
]

row_win = any(all(cell == "X" for cell in row) for row in board)
column_win = any(all(row[i] == "X" for row in board) for i in range(3))
diagonal_win = all(board[i][i] == "X" for i in range(3))
print("Row win:", row_win)
print("Column win:", column_win)
print("Diagonal win:", diagonal_win)

Expected outputRow win: False
Column win: True
Diagonal win: True

3Counting matches with sum()

A comparison gives True or False, and True counts as 1, so sum() adds up the matches. Dividing by len() turns the count into a percentage.

Counting matches with sum()

attendance = ["present", "absent", "present", "present", "late", "present"]

present = sum(status == "present" for status in attendance)
late_or_absent = sum(1 for status in attendance if status != "present")
print(present, "present,", late_or_absent, "late or absent")
print(f"Attendance: {present / len(attendance):.0%}")

Expected output4 present, 2 late or absent
Attendance: 67%

4The first match, with a fallback

next() pulls one item out of a generator expression and stops there, so the rest of the list is never examined. The second argument is returned when nothing matches.

The first match, with a fallback

invoices = [("INV-1", 0), ("INV-2", 12), ("INV-3", 30)]   # (id, days overdue)

first_overdue = next((inv for inv, days in invoices if days > 0), None)
print(first_overdue)
print(next((inv for inv, days in invoices if days > 90), "none"))

Expected outputINV-2
none

5min() and max() with key and default

key= tells min and max what to compare, here each item's price. default= is what you get for an empty collection instead of a ValueError.

min() and max() with key and default

prices = {"pen": 1.5, "ink": 8.0, "tape": 2.25, "stapler": 9.25}
in_stock = ["ink", "tape", "stapler"]

print(min(in_stock, key=prices.get))
print(max(in_stock, key=prices.get))
print(min([], key=prices.get, default="nothing in stock"))

Expected outputtape
stapler
nothing in stock

6Is a list sorted? all() over neighbouring pairs

zip(values, values[1:]) pairs each item with the one after it, and all() checks every pair. Lists with zero or one item have no pairs, so they count as sorted.

Is a list sorted? all() over neighbouring pairs

def is_sorted(values):
    return all(a <= b for a, b in zip(values, values[1:]))

print(is_sorted([1, 3, 3, 8]))
print(is_sorted([4, 2, 9]))
print(is_sorted([]), is_sorted([7]))

Expected outputTrue
False
True True

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