How to get a complex number as a user input in python?
<p>I'm trying to build a calculator that does basic operations of complex numbers. I'm using code for a calculator I found online and I want to be able to take user input as a complex number. Right now the code uses int(input) to get integers to evaluate, but I want the input to be in the form of a complex number with the format complex(x,y) where the user only needs to input x,y for each complex number. I'm new to python, so explanations are encouraged and if it's something that's just not possible, that'd be great to know. Here's the code as it is now:</p>

<pre><code># define functions
def add(x, y):
   """This function adds two numbers"""

   return x + y

def subtract(x, y):
   """This function subtracts two numbers"""

   return x - y

def multiply(x, y):
   """This function multiplies two numbers"""

   return x * y

def divide(x, y):
   """This function divides two numbers"""

   return x / y

# take input from the user
print("Select operation.")
print("1.Add")
print("2.Subtract")
print("3.Multiply")
print("4.Divide")

choice = input("Enter choice: 1, 2, 3, or 4: ")

num1 = int(input("Enter first number: "))
num2 = int(input("Enter second number: "))

if choice == '1':
   print(num1,"+",num2,"=", add(num1,num2))

elif choice == '2':
   print(num1,"-",num2,"=", subtract(num1,num2))

elif choice == '3':
   print(num1,"*",num2,"=", multiply(num1,num2))

elif choice == '4':
   print(num1,"/",num2,"=", divide(num1,num2))
else:
   print("Invalid input")
</code></pre>

<p>Pass your input to the <code>complex</code> type function. This constructor can also be called with a string as argument, and it will attempt to parse it using Python's representation of complex numbers.</p>

<p>Example</p>

<pre><code>my_number = complex(input("Number"))
</code></pre>

<p>Note that Python uses "j" as a symbol for the imaginary component; you will have to tell your user to input numbers in this format: <code>1+3j</code></p>

<p>If you would like your calculator to support a different syntax, you will have to parse the input and feed it to the <code>complex</code> constructor yourself. Regular expressions may be of help.</p>

python python-2.7 input calculator complex-numbers