Error in python calculator I made

Question

I attempted to write a program in python that calculates (likely horribly inefficiently, but I digress) using several different operations. However, there was an error I can't figure out when running it. I think it requires defining the type of a variable. The program:

import math
print('Select a number.')
y = input()
print('Select another number.')
x = input()
print('Select what operation you wish to perform. (e for exponentiation, d for division, m for multiplication, a for addition, s for subtraction, mo for modulo, l for log (the base is the first number you entered), r for root)')
z = input()
if z == 'e' or z == 'E':
 print('The answer is ' + y**x)
elif z == 'd' or z == 'D':
 print('The answer is ' + y/z)
elif z == 'm' or z == 'M':
 print('The answer is ' + y*x)
elif z == 'a' or z == 'A':
 print('The answer is ' + y+x)
elif z == 's' or z == 'S':
 print('The answer is ' + y-x)
elif z == 'mo' or z == 'Mo':
 print('The answer is ' + y%x)
elif z == 'l' or z == 'L':
 print('The answer is ' + math.log(x,y))
elif z == 'r' or z == 'R':
 print('The answer is ' + y**(1/x))

The error that showed up in the shell:

Traceback (most recent call last):
 File "C:/Users/UserNameOmitted/Downloads/Desktop/Python/Calculator.py", line 7, in <module>
 z = input()
 File "<string>", line 1, in <module>
NameError: name 'd' is not defined

• Lafexlos: Use raw_input instead of input.
• Jongware: Are you sure? That line number is weird – The error I get online is "Traceback (most recent call last): File "python", line 11, in <module> TypeError: unsupported operand type(s) for /: 'str' and 'str'". Which suggests this is a dup of stackoverflow.com/questions/24412000/…

Answer 1

You have several problems here:

1. z should be inputted with raw_input, not input.
2. In the division case, you're dividing y/z instead of y/x.

• itzMEonTV: OP is using python2.7. So input gives an int

Answer 2

You have to do

z = raw_input()

Also input returns as int in python2.x.So use raw_input to read as str Then everywhere like print('The answer is ' + y**x) into print('The answer is ' + str(y**x))

• Mathime: What about for math.log(x,y)? Would that become str(math.log(x,y))?
• Mathime: Also, this yields 16/5 = 3.
• itzMEonTV: if you want decimal answer, do from __future__ import division at top of your file
• gboffi: Which is a better choice? print('a string ' + str(num_expr)) or print 'a string', num_expr?

Answer 3

Your code has errors

1. use raw_input() to take string input instead of input()
2. use int(raw_input()) to take integer input, its not an error but it is good practice.
3. you tried to divide int with string.
4. You tried to concatenate string and integer.

Your code should be something like this.

import math
print('Select a number.')
y = int(raw_input())
print('Select another number.')
x = int(raw_input())
print('Select what operation you wish to perform. (e for exponentiation, d for division, m for multiplication, a for addition, s for subtraction, mo for modulo, l for log (the base is the first number you entered), r for root)')
z = raw_input()
if z == 'e' or z == 'E':
 print('The answer is %d' %(y**x))
elif z == 'd' or z == 'D':
 print('The answer is %d' %(y/x))
elif z == 'm' or z == 'M':
 print('The answer is %d' %(y*x))
elif z == 'a' or z == 'A':
 print('The answer is %d' %(y+x))
elif z == 's' or z == 'S':
 print('The answer is %d' %(y-x))
elif z == 'mo' or z == 'Mo':
 print('The answer is %d' %(y%x))
elif z == 'l' or z == 'L':
 print('The answer is %d' %(math.log(x,y)))
elif z == 'r' or z == 'R':
 print('The answer is %d' %(y**(1/x)))