Python program to count positive and negative numbers in a list

In this article, we will explore various methods to count positive and negative numbers in a list. The simplest way to do this is by using a loop. This method counts the positive and negative numbers in a list by iterating through each element using for loop.

a = [10, -20, 30, -40, 50, -60, 0]

# Counts the positive numbers
pos = 0

# Counts the negative numbers
neg = 0

# Iterate through the list
for n in a:
    if n > 0:
        pos += 1
    elif n < 0:
        neg += 1

print(pos)
print(neg)

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Let's explore other different method:

Using filter() Function

filter() function can be used to filter positive and negative numbers and we can count them using len(). It is better than a manual loop since it avoids the explicit creation of new lists during iteration.

a = [10, -20, 30, -40, 50, -60, 0]

# Count positive numbers using filter
pos = len(list(filter(lambda x: x > 0, a)))

# Count negative numbers using filter
neg = len(list(filter(lambda x: x < 0, a)))

print(pos)
print(neg)

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Using List Comprehension

List comprehension provides a more concise way to count positive and negative numbers. It iterate through the list and create new lists based on conditions.

a = [10, -20, 30, -40, 50, -60, 0]

# Count positive numbers
pos = len([n for n in a if n > 0])

# Count negative numbers
neg = len([n for n in a if n < 0])

print(pos)
print(neg)

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