Python Function inputs -

i trying teach myself python on code academy , have written following basic code, not working whatever input outcome 'please enter valid number' , message saying "oops, try again! make sure area_of_circle takes 1 input (radius)."

import math  radius = raw_input("enter radius of circle")  def area_of_circle(radius):     if type(radius) == int:         return math.pi() * radius**2     elif type(radius) == float:         return math.pi() * radius**2     else:         return "'please enter valid number'"  print "your circle area " + area_of_circle(radius) + " units squared" 

the original assignment is:

write function called area_of_circle takes radius input , returns area of circle. area of circle equal pi times radius squared. (use math.pi in order represent pi.)

errors in program:

1. raw_input() returns string, you've convert float or int first.
2. type checking bad idea in python
3. math.pi() not function use math.pi

use exception handling convert string number:

import math radius = raw_input("enter radius of circle: ") def area_of_circle(radius):     try :         f = float(radius) #if conversion fails `except` block handle         return math.pi * f**2   #use math.pi     except valueerror:         return "'please enter valid number'"  print "your circle area {0} units squared".format(area_of_circle(radius))