Python how to run a function with three inputs
Since the doc line is below the states, I am trying to write python code that takes 3 arguments (floating point numbers) and returns one value. For example, entry low is 1.0, hi is 9.0, and fraction is 0.25. This returns 3.0, which is 25% from 1.0 to 9.0. This is what I want, the correct "return" equation is correct. I can run it in python shell and it gives the correct answer.
But, when I run this code to try and request user inputs, it keeps saying:
"NameError: name" low "is undefined"
I just want to run it and get the prompt "Enter low, hi, fraction:" and then the user will enter, for example, "1.0, 9.0, 0.25" and then it will return "3.0".
How do you define these variables? How do I create a print instruction? How to do it?
def interp(low,hi,fraction): #function with 3 arguments
""" takes in three numbers, low, hi, fraction
and should return the floating-point value that is
fraction of the way between low and hi.
"""
low = float(low) #low variable not defined?
hi = float(hi) #hi variable not defined?
fraction = float(fraction) #fraction variable not defined?
return ((hi-low)*fraction) +low #Equation is correct, but can't get
#it to run after I compile it.
#the below print statement is where the error occurs. It looks a little
#clunky, but this format worked when I only had one variable.
print (interp(low,hi,fraction = raw_input('Enter low,hi,fraction: ')))
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raw_input()
only returns one row. You either need to use raw_input()
three times or you need to accept comma separated values and separate them.
Asking 3 questions is much easier:
low = raw_input('Enter low: ') high = raw_input('Enter high: ') fraction = raw_input('Enter fraction: ') print interp(low, high, fraction)
but splitting might work as well:
inputs = raw_input('Enter low,hi,fraction: ')
low, high, fraction = inputs.split(',')
It will fail unless the user gives exactly 3 values with commas in between.
Your own attempt was seen by Python as passing in two positional arguments (passing values from low
and variables hi
) and a keyword argument with the value taken from the call raw_input()
(name argument fraction
). Since there are no variables low
and hi
, you will get NameError
before the call is made raw_input()
.
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