`all()` Function in Python [ English ]

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1. Introduction

The all() function in Python is a built-in function used to check whether all elements in an iterable are True. It returns True only if every element in the iterable evaluates to True. If any element is False, the function returns False.

The all() function is commonly used when a program needs to verify that all conditions in a sequence are satisfied.

2. Syntax

all(iterable)

Parameter

• iterable Any iterable object such as a list, tuple, set, or dictionary containing elements that can be evaluated as True or False.

3. Return Value

• Returns True if all elements are True.
• Returns False if any element is False.
• Returns True if the iterable is empty.

4. Basic Example

numbers = [True, True, True]

print(all(numbers))

Output

True

Explanation

• All elements in the list are True, so the function returns True.

5. Example with False Value

values = [True, False, True]

print(all(values))

Output

False

Explanation

• Since one element is False, the function returns False.

6. Example with Numbers

numbers = [1, 2, 3, 4]

print(all(numbers))

Output

True

Explanation

• In Python, non-zero numbers are considered True.
• Since all numbers are non-zero, the result is True.

7. Example with Zero

numbers = [1, 2, 0, 4]

print(all(numbers))

Output

False

Explanation

• 0 is considered False in Python.
• Because of this, the function returns False.

8. Example with Conditions

numbers = [2, 4, 6, 8]

result = all(n % 2 == 0 for n in numbers)

print(result)

Output

True

Explanation

• The condition checks whether all numbers are even.
• Since every number satisfies the condition, the result is True.

9. Practical Example

marks = [70, 80, 90, 65]

passed = all(mark >= 50 for mark in marks)

print("All students passed:", passed)

Output

All students passed: True

Explanation

• The program checks if all marks are greater than or equal to 50.

10. Summary

• all() is a built-in Python function used to check whether all elements in an iterable are True.
• It returns True only when every element evaluates to True.
• If any element is False, it returns False.
• An empty iterable returns True.
• It is commonly used for validating multiple conditions in programs.