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Python Program to Count Positive and Negative Numbers in a List

Beginner · Lists

A positive number is greater than 0 and a negative number is less than 0, while 0 itself is neither. This program goes through a list and counts how many numbers fall into each of the three groups.

Program

count_positive_negative.py
numbers = [12, -7, 0, 45, -3, 8, 0, -19, 6] # or: numbers = [int(x) for x in input("Enter numbers: ").split()]
positive = 0
negative = 0
zero = 0
for num in numbers:
if num > 0:
positive += 1
elif num < 0:
negative += 1
else:
zero += 1 # neither positive nor negative
print("List:", numbers)
print("Positive numbers:", positive)
print("Negative numbers:", negative)
print("Zeros:", zero)
Output
List: [12, -7, 0, 45, -3, 8, 0, -19, 6]
Positive numbers: 4
Negative numbers: 3
Zeros: 2

How it works

  1. Three counters start at 0, one for each group.
  2. if num > 0 catches the positive numbers and elif num < 0 the negative ones.
  3. A number that is neither greater nor less than 0 must be 0, so the else branch counts the zeros.
  4. The three counts always add up to the length of the list, 9 here.

Other ways to write it

Collecting the numbers in lists

Collecting the numbers in lists
numbers = [12, -7, 0, 45, -3, 8, 0, -19, 6]
positives = [n for n in numbers if n > 0]
negatives = [n for n in numbers if n < 0]
print(f"Positive ({len(positives)}):", positives)
print(f"Negative ({len(negatives)}):", negatives)
Output
Positive (4): [12, 45, 8, 6]
Negative (3): [-7, -3, -19]

List comprehensions keep the numbers themselves, so you can print them as well as count them.

Counting with sum()

Counting with sum()
numbers = [12, -7, 0, 45, -3, 8, 0, -19, 6]
print("Positive numbers:", sum(n > 0 for n in numbers))
print("Negative numbers:", sum(n < 0 for n in numbers))
Output
Positive numbers: 4
Negative numbers: 3

Each comparison gives True or False, and Python treats True as 1 and False as 0, so adding them up counts the numbers that pass.

Try it yourself

Add a sum of the positive numbers and a sum of the negative numbers to the program.

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