Python | Solve given list containing numbers and arithmetic operators

Given a list containing numbers and arithmetic operators, the task is to solve the list.

Example:

Input: lst =  [2, '+', 22, '+', 55, '+', 4]
Output: 83

Input: lst =  [12, '+', 8, '-', 5]
Output: 15

Below are some ways to achieve the above tasks.

Method #1: Using Iteration
We can use iteration as the simplest approach to solve the list with importing different operators.

# Python code to solve the list 
# containing numbers and arithmetic operators 
  
# Importing 
from operator import add, sub 
  
# Function to solve list 
def find(Input): 
    ans = 0
    options = {'+': add, '-': sub} 
    option = add  
    for item in Input: 
        if item in options: 
            option = options[item] 
        else: 
            number = float(item) 
            ans = option(ans, number) 
    return ans 
  
# Input Initialization 
lst = [91, '+', 132, '-', 156, '+', 4] 
  
# Calling function 
Output = find(lst) 
  
# Printing output 
print("Initial list", lst) 
print("Answer after solving list is:", Output) 

Output:

Initial list [91, '+', 132, '-', 156, '+', 4]
Answer after solving list is: 71.0

Method #2: Using eval and join

# Python code to solve the list 
# containing numbers and arithmetic operators 
  
# Input list initialization 
lst =  [2, '+', 22, '+', 55, '+', 4] 
  
# Using eval and join 
Output = eval(' '.join(str(x) for x in lst)) 
  
# Printing output 
print("Initial list", lst) 
print("Answer after solving list is:", Output) 

Output:

Initial list [2, '+', 22, '+', 55, '+', 4]
Answer after solving list is: 83

Attention geek! Strengthen your foundations with the Python Programming Foundation Course and learn the basics.

To begin with, your interview preparations Enhance your Data Structures concepts with the Python DS Course.

My Personal Notes

Recommended Posts: