python - equation builder using loops -

i'm trying write program iterates through possible simple equations find value of 24. managed loop done there i'm not catching.

the idea theres 3 level loop (i guess theta(n^3)?, im bad time complexity), used build equation 4 numbers (randomly generated in program) added list.

numlist = [x2, x3, x4] 

here code have:

for in range(4):     j in range(4):         k in range(4):             l in range(len(numlist)):                 n += 1                 print(i, j, k, " i, j, k")                 print(x2, x3, x4, "x2, x3, x4")                 print(x, "x supposed reset")                 print(l, "val of l")                 print(n, "val of n")                 if == 0 or j == 0 or k == 0:                     x += "+"                     x += str(numlist[n])                     print(x, "add")                 if == 1 or j == 1 or k == 1:                     x += "-"                     x += str(numlist[n])                     print(x, "sub")                 if == 2 or j == 2 or k == 2:                     x += "*"                     x += str(numlist[n])                     print(x, "mult")                 if == 3 or j == 3 or k == 3:                     x += "/"                     x += str(numlist[n])                     print(x, "div")                  if n == 2:                             print()                     print("----")                     print(x, "final")                     print(eval(x), "evald")                     if eval(x) not 24:                         x = x1                         print(x, "x reset")                     else:                         print(eval(x), "= 24")                     n = -1                     print("----") 

the error comes in when, reason, string i'm building , evaluating (x) not reset, , instead adds same string generated in last loop iteration (it's supposed default value). default value of x randomly generated:

x = str(randrange(1, 9)) 

it's weird me, i'm not sure going wrong, loop acting switch conditional statement without breaks. here console output: pasted pastebin

can tell me doing wrong? or going on in code not seeing why x not being reset if new string being built (this want)?

edit: here entire source: equation.py

the problem isn't 'x isn't being reset'. problem code not designed use 3 operators on each pass through. example, if 0, j 1 , k 2 use + due being 0, - due j being 1 , * due k being 2, every single number in equation, you'd see things 1+5-5*5+6-6*6+4-4*4 of operators repeated 3 times.

you want logic more this, explicitly use 3 operators , iterate on combinations of 3 operators:

from random import randrange  def brute_force():     x1 = randrange(1, 9)     x2 = randrange(1, 9)     x3 = randrange(1, 9)     x4 = randrange(1, 9)     numlist = [x1, x2, x3, x4]     operatorlist = ["+", "-", "/", "*"]     equation = ""      in range(4):         j in range(4):             k in range(4):                 equation = str(numlist[0]) + operatorlist[i] + str(numlist[1]) + operatorlist[j] + str(numlist[2]) + operatorlist[k] + str(numlist[3])                 print("equation: " + equation)                 print("evaluation: " + str(eval(equation)))  if __name__ == "__main__":     brute_force() 

output looks like

>>> brute_force() equation: 4+6+4+6 evaluation: 20 equation: 4+6+4-6 evaluation: 8 equation: 4+6+4/6 evaluation: 10 equation: 4+6+4*6 evaluation: 34 equation: 4+6-4+6 evaluation: 12 equation: 4+6-4-6 evaluation: 0 equation: 4+6-4/6 evaluation: 10 ...