Python program to print all negative numbers in a range

Given the start and end of a range, write a Python program to print all negative numbers in a given range.

Examples:

Input: a = -4, b = 5
Output: -4, -3, -2, -1

Input: a = -3, b= 4
Output: -3, -2, -1

Method: Print all the negative numbers using a single-line solution.

Print all negative numbers using for loop. Define the start and end limits of the range. Iterate from start range to end range using for loop and check if num is less than 0. If the condition satisfies, then only print the number. 

Python3

# Python code
# To print all negative numbers in a given range


def negativenumbers(a,b):
  # Checking condition for negative numbers
  # single line solution
  out=[i for i in range(a,b+1) if i<0]
  # print the all negative numbers
  print(*out)

# driver code
# a -> start range
a=-4
# b -> end range
b=5
negativenumbers(a,b)

Output

-4 -3 -2 -1

Time Complexity: O(n)
Auxiliary Space: O(1)

Example #1: Print all negative numbers from the given list using for loop Define start and end limit of the range. Iterate from start till the range in the list using for loop and check if num is less than 0. If the condition satisfies, then only print the number. 

Python3

# Python program to print negative Numbers in given range

start, end = -4, 19

# iterating each number in list
for num in range(start, end + 1):

    # checking condition
    if num < 0:
        print(num, end = " ")

Output

-4 -3 -2 -1 

Example #2: Taking range limit from user input 

Python3

# Python program to print negative Numbers in given range

start = int(input("Enter the start of range: "))
end = int(input("Enter the end of range: "))

# iterating each number in list
for num in range(start, end + 1):

    # checking condition
    if num < 0:
        print(num, end = " ")

Output:

Enter the start of range: -15
Enter the end of range: 5
-15 -14 -13 -12 -11 -10 -9 -8 -7 -6 -5 -4 -3 -2 -1 

Method: Using lambda function 

Python3

# Python code To print all negative
# numbers in a given range using lambda function

# inputs
a=-4;b=5
li=[]
for i in range(a,b):
    li.append(i)
# printing negative numbers using the lambda function
negative_num = list(filter(lambda x: (x<0),li))
print(negative_num)

Output

[-4, -3, -2, -1]

Time Complexity: O(n)
Auxiliary Space: O(n), where n is length of list

Method: Using enumerate function

Python3

a=-4;b=5;l=[]
for i in range(a,b+1):
  l.append(i)
print([a for j,a in enumerate(l) if a<0])

Output

[-4, -3, -2, -1]

Method: Using list comprehension

Python3

a=-4;b=5
print([i for i in range(a,b+1) if i<0])

Output

[-4, -3, -2, -1]

Method: Using pass()  

Python3

a=-4;b=5
for i in range(a,b+1):
  if i>=0:
    pass
  else:
    print(i,end=" ")

Output

-4 -3 -2 -1 

Method: Using recursion

Python3

#Recursive function to print Negative numbers
def PrintNegative(itr,end):
  if itr == end: #Base Condition
    return
  if itr < 0:  #checking Negative or not
    print(itr,end=" ")
  PrintNegative(itr+1,end)  #Recursive function call
  return
a = -5
b = 5
PrintNegative(a,b)

Output

-5 -4 -3 -2 -1 

Method: Using numpy.arange() and numpy.where():

note: install numpy module using command “pip install numpy”

Here’s the method to print all negative numbers in a range using numpy.arange() and numpy.where():

Algorithm:

Take input values for start and end of the range.
Create an array using numpy.arange() with the start and end values.
Use numpy.where() to filter the negative numbers from the array.
Print the resulting array.
Python code:

Python3

import numpy as np

# Taking input values for start and end of the range
start = -4
end = 5

# Creating an array using numpy.arange()
arr = np.arange(start, end+1)

# Filtering negative numbers using numpy.where()
neg_arr = arr[np.where(arr<0)]

# Printing the resulting array
print(neg_arr)

Output:

[-4 -3 -2 -1]

Time complexity: O(n) for arange function.
Auxiliary space: O(n), where n is the length of the array generated by numpy.arange().