+- Python Forum (https://python-forum.io)
+-- Forum: Python Coding (https://python-forum.io/forum-7.html)
+--- Forum: General Coding Help (https://python-forum.io/forum-8.html)
+--- Thread: User input to calculate Area or Radius of Circle (/thread-22360.html)
User input to calculate Area or Radius of Circle - DustinKlent - Nov-10-2019
I'm writing a practice script to prompt the user to input "Area" or "Radius", then input the area or radius of a circle to calculate the other.
I wanted to use functions to do it.
Here's what I've got so far:
import math
from math import pi
def area():
radius = float(input("To calculate the Area enter the Radius of the circle: "))
area = float(pi)*pow(radius,2)
print("The Area is " + str(area))
def radius():
area = float(input("To calculate the Radius enter the Area of the circle: "))/pi
radius = str(math.sqrt(area))
print("The Radius is " + radius)
choice = {'Radius': radius, 'Area': area}
action = input("Calculate Area or Radius? ")
action = action.capitalize()
choice[action]()Is there a superior way to do this? Are there any lines I can cut or condense?
RE: User input to calculate Area or Radius of Circle - ichabod801 - Nov-10-2019
Superior would be functions with parameters and return values, which are far more versatile. I also like if __name__ blocks. There are very often lines to cut, but that doesn't mean you want to cut them. You could do:
import math
def area(radius):
return math.pi * radius ** 2
def radius(area):
return math.sqrt(area / math.pi)
if __name__ == '__main__':
choices = {'Radius': (radius, 'Radius', 'Area'), 'Area': (area, 'Area', 'Radius')}
action, calculate, given = choices[input("Calculate Area or Radius? ").capitalize()]
result = action(float(input('To calculate the {}, input the {}: '.format(calculate, given))))
print('The {} is {:.2f}.'.format(calculate, result))But that is perhaps excessive.
RE: User input to calculate Area or Radius of Circle - DustinKlent - Nov-10-2019
Thank you.
RE: User input to calculate Area or Radius of Circle - Gribouillis - Nov-10-2019
Here is a variation on the same concept. It is longer but there a richer parsing of user input and an extended functionality
from math import pi, sqrt
class Interaction:
def ask_parameter(self):
prompt = """\
Please enter one of the circle's parameter. You may enter
"radius <number>" or "circumference <number>"
or "diameter <number>" or "area <number>". You may also
use r, c, d, a to abbreviate these words.
Your choice: """
while True:
reply = input(prompt).strip().split()
if len(reply) != 2:
self.say_invalid_input()
continue
param = reply[0].lower()
if not param in [
'radius', 'circumference', 'diameter', 'area',
'r', 'c', 'd', 'a']:
self.say_invalid_input()
continue
param = param[0]
try:
value = float(reply[1])
except ValueError:
self.say_invalid_input()
continue
else:
if value < 0:
print('ERROR: value must be non negative, try again.')
continue
if param == 'd':
self.r = value / 2
elif param == 'a':
self.r = sqrt(value / pi)
elif param == 'c':
self.r = value / (2 * pi)
else:
self.r = value
return
def display_results(self):
print("""\
area = {a}
circumference = {c}
diameter = {d}
radius = {r}""".format(
r = repr(self.r),
a = repr(pi * self.r ** 2),
c = repr(self.r * 2 * pi),
d = repr(self.r * 2)
))
def say_invalid_input(self):
print('ERROR: invalid input, try again.')
def run(self):
self.ask_parameter()
self.display_results()
if __name__ == '__main__':
Interaction().run()Example in a consoleOutput:λ python3 paillasse/circle.py
Please enter one of the circle's parameter. You may enter
"radius <number>" or "circumference <number>"
or "diameter <number>" or "area <number>". You may also
use r, c, d, a to abbreviate these words.
Your choice: diameter 23
area = 415.4756284372501
circumference = 72.25663103256524
diameter = 23.0
radius = 11.5