Python Program to Count Positive and Negative Numbers in a List

Write a Python Program to Count Positive and Negative Numbers in a List using For Loop, While Loop, and Functions with practical example.

Before you start, please refer List article to understand everything about Lists.

Python Program to Count Positive and Negative Numbers in a List using For Loop

In this python program, we are using For Loop to iterate each and every element in a given List. Inside the loop we are using If statement to check and count Positive and Negative numbers.

# Python Program to Count Positive and Negative Numbers in a List

NumList = []
Positive_count = 0
Negative_count = 0

Number = int(input("Please enter the Total Number of List Elements: "))
for i in range(1, Number + 1):
    value = int(input("Please enter the Value of %d Element : " %i))
    NumList.append(value)

for j in range(Number):
    if(NumList[j] >= 0):
        Positive_count = Positive_count + 1
    else:
        Negative_count = Negative_count + 1

print("\nTotal Number of Positive Numbers in this List =  ", Positive_count)
print("Total Number of Negative Numbers in this List = ", Negative_count)

OUTPUT

ANALYSIS
User entered elements = [12, -22, 3, 5], Positive_count = 0, Negative_count = 0

For Loop – First Iteration: for 0 in range(0, 4)
The condition is True so, compiler will enter into the If Statement
if(NumList[0] >= 0) => if(12 >= 0) – Condition is True
Positive_count = Positive_count + 1 => 0 + 1 = 1

Second Iteration: for 1 in range(0, 4) – Condition is True
if(NumList[1] >= 0) => if(-22 >= 0) – Condition is False
Compiler will enter into the Else block.
Negative_count = Negative_count + 1 => 0 + 1 = 1

Third Iteration: for 2 in range(0, 4) – Condition is True
if(NumList[2] >= 0) => if(3 >= 0) – Condition is True
Positive_count = 1 + 1 => 2

Fourth Iteration: for 3 in range(0, 4) – Condition is True
if(5 >= 0) – Condition is True
Compiler will enter into the Else block.
Positive_count = 2 + 1 => 3

Fifth Iteration: for 4 in range(4) – Condition is False
So compiler will exit from For Loop

Python Program to Count Positive and Negative Numbers in a List using While loop

This program for counting positive and negative numbers is same as above. We just replaced the For Loop with While loop.

# Python Program to Count Positive and Negative Numbers in a List

NumList = []
Positive_count = 0
Negative_count = 0
j = 0

Number = int(input("Please enter the Total Number of List Elements: "))
for i in range(1, Number + 1):
    value = int(input("Please enter the Value of %d Element : " %i))
    NumList.append(value)

while(j < Number):
    if(NumList[j] >= 0):
        Positive_count = Positive_count + 1
    else:
        Negative_count = Negative_count + 1
    j = j + 1

print("\nTotal Number of Positive Numbers in this List =  ", Positive_count)
print("Total Number of Negative Numbers in this List = ", Negative_count)

OUTPUT

Python Program to Count Positive and Negative items in a List using Functions

This program is same as first example. However, we separated the logic using Functions

# Python Program to Count Positive and Negative Numbers in a List

def count_Positive(NumList):
    Positive_count = 0
    for j in range(Number):
        if(NumList[j] >= 0):
            Positive_count = Positive_count + 1
    return Positive_count

def count_Negative(NumList):
    Negative_count = 0
    for j in range(Number):
        if(NumList[j] % 2 != 0):
            Negative_count = Negative_count + 1
    return Negative_count

NumList = []
Number = int(input("Please enter the Total Number of List Elements: "))
for i in range(1, Number + 1):
    value = int(input("Please enter the Value of %d Element : " %i))
    NumList.append(value)

Positive_cnt = count_Positive(NumList)
Negative_cnt = count_Negative(NumList)
print("\nTotal Number of Positive Numbers in this List =  ", Positive_cnt)
print("Total Number of Negative Numbers in this List = ", Negative_cnt)

OUTPUT