Multiply and Addition in the same loop statement with logic.

Multiply and Addition in the same loop statement with logic. - Printable Version

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Multiply and Addition in the same loop statement with logic. - joelraj - Jan-31-2023

Hi Python Community,

Greetings to you all !

After the if statement is passed through Reven and Rodd have to take two alternative indexes: one has to do multiply, and another has to do add.

like example,

Output:array has {0,1,2,3,4,5,6,7,8,9}
Reven = ((((A[0]*A[2])+A[4])*A[6])+A[8])
like 
0 +2
2 *4
8 +6
14 *8

array has {0,1,2,3,4,5,6,7,8,9}
Reven = ((((A[1]*A[3])+A[5])*A[7])+A[9])
like 
1 + 3
4 * 5
20 +7
27 * 8

wriiten code

def AddMult(A):
    Reven = 0
    Rodd = 0
    for i in range(len(A)):
        if i % 2 == 0:
            Reven = Reven + A[i]
        else:
            Rodd = Rodd + A[i]

    E = (Reven%2)
    O = (Rodd%2)
    if(O > E):
        return "ODD"
    elif(E > O):
        return "EVEN"
    elif(O == E):
        return "NEUTRAL"

Could you please help me solve this?

RE: Multiply and Addition in the same loop statement with logic. - tester_V - Jan-31-2023

Buddy, use the 'insert Python' button to post your snipped. Wink

RE: Multiply and Addition in the same loop statement with logic. - deanhystad - Feb-02-2023

Which is it?

Reven = ((((A[0]*A[2])+A[4])*A[6])+A[8])

Reven = (0 * 2 + 4) * 6 + 8 = 32

Reven = ((0 + 2) * 4 + 6) * 8 = 112

When solving something like this I perform the operation by hand and look for a pattern.

values = (0, 1, 2, 3, 4, 5, 6, 7, 8, 9)
result = [0, 0] # result for even, odd

Output:index  value operator result     Description
  0      0       +    [0, 0]     result[0] += 0
  1      1       +    [0, 1]     result[1] += 1
  2      2       *    [0, 1]     result[0] *= 2
  3      3       *    [0, 3]     result[1] *= 3
  4      4       +    [4, 3]     result[0] += 4
  5      5       +    [4, 8]     result[1] += 5
  6      6       *    [24, 8]    result[0] *= 6
  7      7       *    [24, 56]   result[1] *= 7
  8      8       +    [32, 56]   result[0] += 8
  9      9       +    [32, 65]   result[1] += 9

The index for result[index] has a period 2 cycle: 0, 1
The operator has a period 4 cycle: +, +, *, *

Using that information I might write the function like this:

from operator import add, mul

def add_mul(numbers):
    result = [0, 0]
    for i, number in enumerate(numbers):
        result[i % 2] = (add, add, mul, mul)[i % 4](result[i % 2], number)
    return result

I don't quite understand the even/odd evaluation at the end, but this code:

    E = (Reven%2)
    O = (Rodd%2)
    if(O > E):
        return "ODD"
    elif(E > O):
        return "EVEN"
    elif(O == E):
        return "NEUTRAL"

Can be written like this:

even, odd = (result % 2 for result in add_mul(range(10)))
print("NEUTRAL" if (even == odd) else "EVEN" if even else "ODD")

In Python, 0 is falsey and 1 is truey. If you know the only possible values are 0 and 1 you don't need to do comparisons like E > O.

And about using "O" as a variable. Don't do it. Capital o looks like zero, just like lower case L looks like one. Avoid using either to avoid any confusion.