Python | Subtract two list elements if element in first list is greater

Given two list, If element in first list in greater than element in second list, then subtract it, else return the element of first list only.

Examples:

Input:
l1 = [10, 20, 30, 40, 50, 60]
l2 = [60, 50, 40, 30, 20, 10]
Output:
[10, 20, 30, 10, 30, 50]

Input:
l1 = [15, 9, 10, 56, 23, 78, 5, 4, 9]
l2 = [9, 4, 5, 36, 47, 26, 10, 45, 87]
Output:
[6, 5, 5, 20, 23, 52, 5, 4, 9]

Method 1: The naive approach is to traverse both list simultanously and if the element in first list in greater than element in second list, then subtract it, else if the element in first list in smaller than element in second list, then return element of first list only.

filter_none

edit
close

play_arrow

link
brightness_4
code

# Python code to subtract if element in first 
# list is greater than element in second list, 
# else we output element of first list.
  
# Input list initialisation
Input1 = [10, 20, 30, 40, 50, 60]
Input2 = [60, 50, 40, 30, 20, 10]
  
# Output list initialisation
Output = []
  
for i in range(len(Input1)):
    if Input1[i] > Input2[i]:
        Output.append(Input1[i] - Input2[i])
    else:
        Output.append(Input1[i])
          
print("Original list are :")
print(Input1)
print(Input2)
  
print("\nOutput list is")
print(Output) 

chevron_right


Output:

Original list are :
[10, 20, 30, 40, 50, 60]
[60, 50, 40, 30, 20, 10]

Output list is
[10, 20, 30, 10, 30, 50]

Method 2: Using zip() we subtract if element in first list is greater than element in second list, else we output element of first list.



filter_none

edit
close

play_arrow

link
brightness_4
code

# Python code to subtract if element in first 
# list is greater than element in second list, 
# else we output element of first list.
  
# Input list initialisation
Input1 = [10, 20, 30, 40, 50, 60]
Input2 = [60, 50, 40, 30, 20, 10]
  
# using zip()
Output =[e1-e2 if e1>e2 else e1 for (e1, e2) in zip(Input1, Input2)]
  
# Printing output
print("Original list are :")
print(Input1)
print(Input2)
  
print("\nOutput list is")
print(Output) 

chevron_right


Output:

Original list are :
[10, 20, 30, 40, 50, 60]
[60, 50, 40, 30, 20, 10]

Output list is
[10, 20, 30, 10, 30, 50]

Method 3: Using list comprehension.

filter_none

edit
close

play_arrow

link
brightness_4
code

# Python code to subtract if element in first 
# list is greater than element in second list, 
# else we output element of first list.
  
# Input list initialisation
Input1 = [10, 20, 30, 40, 50, 60]
Input2 = [60, 50, 40, 30, 20, 10]
  
# Output list initialisation
Output = [Input1[i]-Input2[i] if Input1[i] > Input2[i] \
          else Input1[i] for i in range(len(Input1))]
  
# Printing output
print("Original list are :")
print(Input1)
print(Input2)
  
print("\nOutput list is")
print(Output)

chevron_right


Output:

Original list are :
[10, 20, 30, 40, 50, 60]
[60, 50, 40, 30, 20, 10]

Output list is
[10, 20, 30, 10, 30, 50]

Method 4: Using numpy() to complete the above task.

filter_none

edit
close

play_arrow

link
brightness_4
code

# Python code to subtract if element in first 
# list is greater than element in second list, 
# else we output element of first list.
  
   
import numpy as np
  
# Input list initialisation
Input1 = np.array([10, 20, 30, 40, 50, 60])
Input2 = np.array([60, 50, 40, 30, 20, 10])
   
# using numpy
Output = np.where(Input1 >= Input2, Input1 - Input2, Input1)
   
# Printing output
print("Original list are :")
print(Input1)
print(Input2)
  
print("\nOutput list is")
print(Output) 

chevron_right


Output:

Original list are :
[10 20 30 40 50 60]
[60 50 40 30 20 10]

Output list is
[10 20 30 10 30 50]



My Personal Notes arrow_drop_up


If you like GeeksforGeeks and would like to contribute, you can also write an article using contribute.geeksforgeeks.org or mail your article to contribute@geeksforgeeks.org. See your article appearing on the GeeksforGeeks main page and help other Geeks.

Please Improve this article if you find anything incorrect by clicking on the "Improve Article" button below.


Article Tags :

Be the First to upvote.


Please write to us at contribute@geeksforgeeks.org to report any issue with the above content.