freeCodeCamp/curriculum/challenges/english/99-dev-playground/daily-coding-challenges-python/python-challenge-17.md

id, title, challengeType, dashedName

id	title	challengeType	dashedName
6821eca7237de8297eaee79f	Python Challenge 17: Unorder of Operations	29	python-challenge-17

--description--

Given an array of integers and an array of string operators, apply the operations to the numbers sequentially from left-to-right. Repeat the operations as needed until all numbers are used. Return the final result.

For example, given [1, 2, 3, 4, 5] and ['+', '*'], return the result of evaluating 1 + 2 * 3 + 4 * 5 from left-to-right ignoring standard order of operations.

• Valid operators are +, -, *, /, and %.

--hints--

evaluate([5, 6, 7, 8, 9], ['+', '-']) should return 3

({test: () => { runPython(`
from unittest import TestCase
TestCase().assertEqual(evaluate([5, 6, 7, 8, 9], ['+', '-']), 3)`)
}})

evaluate([17, 61, 40, 24, 38, 14], ['+', '%']) should return 38

({test: () => { runPython(`
from unittest import TestCase
TestCase().assertEqual(evaluate([17, 61, 40, 24, 38, 14], ['+', '%']), 38)`)
}})

evaluate([20, 2, 4, 24, 12, 3], ['*', '/']) should return 60

({test: () => { runPython(`
from unittest import TestCase
TestCase().assertEqual(evaluate([20, 2, 4, 24, 12, 3], ['*', '/']), 60)`)
}})

evaluate([11, 4, 10, 17, 2], ['*', '*', '%']) should return 30

({test: () => { runPython(`
from unittest import TestCase
TestCase().assertEqual(evaluate([11, 4, 10, 17, 2], ['*', '*', '%']), 30)`)
}})

evaluate([33, 11, 29, 13], ['/', '-']) should return -2

({test: () => { runPython(`
from unittest import TestCase
TestCase().assertEqual(evaluate([33, 11, 29, 13], ['/', '-']), -2)`)
}})

--seed--

--seed-contents--

def evaluate(numbers, operators):

    return numbers

--solutions--

def do_math(a, b, operator):
    if operator == '+':
        return a + b
    elif operator == '-':
        return a - b
    elif operator == '*':
        return a * b
    elif operator == '/':
        return a / b
    else:
        return a % b

def evaluate(numbers, operators):
    total = numbers[0]

    for i in range(1, len(numbers)):
        operator = operators[(i - 1) % len(operators)]
        total = do_math(total, numbers[i], operator)

    return total