Operations inside variables

Question

I want to make a python script that finds the maximum possible output using 2 operations. The problem it says that there is a syntax error at the 2nd to the last line, in the b in there. How can I fix it?

x = 0
a = int(input("1st number:")) 
c = int(input("2nd number:" )) 
e = int(input("3rd number:" ))
for i in range(4):
    if i == 0:
        b = "+" 
    elif i == 1: 
        b = "-"
    elif i == 2:    
        b = "/"
    else:
        b = "*" 
    for j in range(4):
        if j == 0:
            d = "+" 
        elif j == 1: 
            d = "-" 
        elif j == 2:    
            d = "/" 
        else:
            d = "*" 
        k = a b c d e
        print(k)

You should look into the `operator` module and assign actual functions to `b` and `d` not just strings, then you could do `d(b(a, c), e)`. — AChampion, Aug 20 '17 at 23:10
@AChampion that might not preserve proper operator precedence, though. I'm not sure how trivial that would be to do without `eval`, however. — Izaak van Dongen, Aug 20 '17 at 23:12
@IzaakvanDongen very true, but `eval()` is generally considered dangerous. You could always just assign `b` to the higher precedence operator. — AChampion, Aug 20 '17 at 23:14

score -1 · Answer 1 · answered Aug 20 '17 at 23:09

-1

If all you're after is the variables a to e on a single line, couldn't you just separate them with commas and call Print?

Print a,b,c,d,e

answered Aug 20 '17 at 23:09

neophlegm

375
1
13

Otherwise you need to define k as a proper python type. For instance a tuple: `k=(a,b,c,d,e)` – neophlegm Aug 20 '17 at 23:09
3

I think the idea isn't to get them on a single line but to evaluate the expression, where `b` is expected to act as an operator. – Izaak van Dongen Aug 20 '17 at 23:10
Ah ok. I misunderstood, clearly – neophlegm Aug 21 '17 at 05:22

Petar Toshev · Answer 2 · 2017-08-20T23:17:51.410

-2

k = a b c d e would give you error because this is not permitted. You could do it like:

if b == "+" and d == "+":
    k = a + c + e
elif b == "+" and d == "-":
    k = a + c - e

And etc.

edited Aug 20 '17 at 23:17

answered Aug 20 '17 at 23:06

Petar Toshev

67
1
1
9

That won't fix anything. Firstly, because Python doesn't do scopes inside if statement and for loops, and secondly because the problem is that `a b c d e` is invalid syntax, not a case of a name error. – Izaak van Dongen Aug 20 '17 at 23:08

Operations inside variables

2 Answers2