Telling python to use an operator

[Enderg312]

num1 = input("num1: ")
operator = input("operator: ")
num2 = input("num2: ")

print(num1 + operator + num2)

How can I get python to insert the operator where it goes and to get the answer?

[Sauron]

You need a conditional statement to check what the operator is, then do the relevant operation.

[Enderg312]

How would I do something like that?

[AbydosOne]

Just now, Enderg312 said:

How would I do something like that?

psuedocode:

if (operator == "+")
	return num1 + num2
else if (operator == "-")
	return num1 - num2
else if (operator == "^")
	return num1 ** num2
// etc...

 

[tikker]

Alternatively, to save yourself writing if clauses for every operator, you can build the expression as a string, say "2+2" and either eval or ast.literal_eval that. Be aware that it is good practise to never eval random stuff users can put it, so be sure to sanitise input if you go that route.

[WillLTT]

3 hours ago, Enderg312 said:

num1 = input("num1: ")
operator = input("operator: ")
num2 = input("num2: ")

print(num1 + operator + num2)

--snippet--

 

3 hours ago, AbydosOne said:

psuedocode:

if (operator == "+")
	return num1 + num2
else if (operator == "-")
	return num1 - num2
else if (operator == "^")
	return num1 ** num2
// etc...

 

i agree that this is probably the best solution.

 

But i wanted to add a note:

If you come across the use of the eval function, dont use it, i looks like this:

 

eval("print('helloworld'))

// in your case,
// you can come across this:
// dont use it.

eval("2+2")

DONT use it, it is very very bad pratice.

[FFY00]

You can use the operator module.

 

operator_actions = {
  '+': operator.add,
  '-': operator.sub,
  '*': operator.mul,
  '/': operator.truediv,
  '%': operator.mod,
}

num1 = input('num1: ')
operator = input('operator: ')
num2 = input('num2: ')

print(operator_actions[operator](num1, num2))

 

[adarw]

uhhh.... can someone explain what a operator is? 

[RockSolid1106]

53 minutes ago, adarw said:

uhhh.... can someone explain what a operator is? 

5 + 5 = 10

Here '+' is the operator.

Similarly for other operators like multiplication(*), division(/), subtraction(-), remainder from the division(%), etc.

[adarw]

2 minutes ago, RockSolid1106 said:

5 + 5 = 10

Here '+' is the operator.

Similarly for other operators like multiplication(*), division(/), subtraction(-), remainder from the division(%), etc.

ahhh ok thanks!

[hirushaadi]

On 11/1/2021 at 7:14 AM, adarw said:

uhhh.... can someone explain what a operator is? 

+, -, %, /, //, *, ** are some arithmetic  operators in python, 

=, <=, >=, += are some assignment operators in python, 

>>, <<, &, |, ^ are some bitwise operators in python,

 

You can learn more from here: https://www.w3schools.com/python/python_operators.asp