Python program to print positive numbers in a list

Given a list of numbers, write a Python program to print all positive numbers in given list. 

Example:

Input: list1 = [12, -7, 5, 64, -14]
Output: 12, 5, 64

Input: list2 = [12, 14, -95, 3]
Output: [12, 14, 3]

Example #1: Print all positive numbers from given list using for loop Iterate each element in the list using for loop and check if number is greater than or equal to 0. If the condition satisfies, then only print the number. 

Python3

# Python program to print positive Numbers in a List

# list of numbers
list1 = [11, -21, 0, 45, 66, -93]

# iterating each number in list
for num in list1:

    # checking condition
    if num & gt
    = 0:
        print(num, end=& quot
              & quot
              )

Output:

11 0 45 66 

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

Example #2: Using while loop 

Python3

# Python program to print positive Numbers in a List

# list of numbers
list1 = [-10, 21, -4, -45, -66, 93]
num = 0

# using while loop
while(num < len(list1)):

    # checking condition
    if list1[num] >= 0:
        print(list1[num], end = " ")

    # increment num
    num += 1

Output:

21 93 

Time complexity : O(n)

Space complexity : O(1)

Example #3: Using list comprehension

Python3

# Python program to print Positive Numbers in a List

# list of numbers
list1 = [-10, -21, -4, 45, -66, 93]

# using list comprehension
pos_nos = [num for num in list1 if num >= 0]

print("Positive numbers in the list: ", *pos_nos)

Output:

Positive numbers in the list:  45 93

Time complexity : O(n), where n is length of list.

Auxiliary Space : O(1)

Example #4: Using lambda expressions

Python3

# Python program to print positive Numbers in a List

# list of numbers
list1 = [-10, 21, 4, -45, -66, 93, -11]


# we can also print positive no's using lambda exp.
pos_nos = list(filter(lambda x: (x >= 0), list1))

print("Positive numbers in the list: ", *pos_nos)

Output:

Positive numbers in the list:  21, 4, 93

Time complexity of the program is O(n), where n is the number of elements in the list.

Space complexity of the program is also O(n), where n is the number of elements in the list. 

Method: Using enumerate function 

Python3

l=[12, -7, 5, 64, -14]
print([a for j,a in enumerate(l) if a>=0])

Output

[12, 5, 64]

Method:Using startswith() method

Python3

# Python program to print positive numbers in a List

# list of numbers
list1 = [11, -21, 0, 45, 66, -93]
res=[]
list2=list(map(str,list1))
for i in range(0,len(list2)):
    if( not list2[i].startswith("-") and list2[i] !="0"):
        res.append(str(list1[i]))
res=" ".join(res)
print(res)

Output

11 45 66

Auxiliary Space: O(n)

Time complexity :O(n)

Method: Using Numpy Array: 

Python

# Python program to print Positive Numbers in a List
import numpy as np
# list of numbers
list1 = np.array([-10, -21, -4, 45, -66, 93])

# using numpy Array
pos_nos = list1[list1 >=0];

print("Positive numbers in the list: ", *pos_nos)

Output:

Positive numbers in the list:  45 93

The time complexity of this program is O(n), where n is the number of elements in the input list. 

The space complexity of this program is also O(n), where n is the number of elements in the input list. 

Method: Using recursion

Python3

#Function to print even numbers in a list
def PrintEven(itr,list1):
  if itr == len(list1): #Base Condition
    return
  if list1[itr]>=0:
    print(list1[itr],end = " ")
  PrintEven(itr+1,list1)  #Recursive Function Call
  return

list1 = [-5,7,-19,10,9] #list of numbers
PrintEven(0,list1) #Function Call

#This code is contributed by vinay pinjala

Output

7 10 9 

Time complexity:
The time complexity of this function is O(N), where N is the length of the list list1.

Space complexity:
The space complexity of this function is O(N), where N is the length of the list list1. 

Method : Using operator.ge()

Python3

# Python program to print positive Numbers in a List

# list of numbers
list1 = [-10, 21, 4, -45, -66, 93, -11]

import operator
pos_nos = []
for i in list1:
    if operator.ge(i,0):
        pos_nos.append(i)

print("Positive numbers in the list: ", pos_nos)

Output

Positive numbers in the list:  [21, 4, 93]

Time Complexity : O(N)

Auxiliary Space : O(N)