Access a function from a class in Python?

Question

I was wondering how would I access the "eq" function from my "formula" class? What I have tried does not work and returns "unbound method". Thanks.

class formula(): 
    def eq(): 
        print "What is your Velocity: " 
        v = float(raw_input()) 
        print "What is your Intial Velocity: " 
        u = float(raw_input())  
        print "What is the time: " 
        t = float(raw_input()) 
        aa = v-u 
        answer = aa/t 
        print "Your Acceleration is: ", answer 

a =formula.eq() 

print a

[static methods in python](http://stackoverflow.com/questions/735975/static-methods-in-python) — gongzhitaao, Nov 28 '13 at 21:04
Why is `eq` in `formula` at all? It looks like it belongs at module level. — user2357112, Nov 28 '13 at 21:46

score 3 · Answer 1 · answered Nov 28 '13 at 21:03

You need to give eq a self parameter, and create an instance of formula by calling it:

class formula(): 
    def eq(self): 
        print "What is your Velocity: " 
        v = float(raw_input()) 
        print "What is your Intial Velocity: " 
        u = float(raw_input())  
        print "What is the time: " 
        t = float(raw_input()) 
        aa = v-u 
        answer = aa/t 
        print "Your Acceleration is: ", answer 

formula().eq()

There is no point in storing the return value, you don't return anything here.

I note that you don't actually use anything in your function that requires a class. You could just as well leave the class out here and not lose anything

def eq(): 
    print "What is your Velocity: " 
    v = float(raw_input()) 
    print "What is your Intial Velocity: " 
    u = float(raw_input())  
    print "What is the time: " 
    t = float(raw_input()) 
    aa = v-u 
    answer = aa/t 
    print "Your Acceleration is: ", answer 

eq()

If you wanted to put your formula in a namespace, put it in a separate module instead; put def eq() in a file formula.py and import that as import formula. No point in making eq() a staticmethod here, really.

score 1 · Answer 2 · answered Nov 28 '13 at 21:04

make it like a static method

class formula(): 
    @staticmethod
    def eq():
        v = float(raw_input("What is your Velocity: ")) 
        u = float(raw_input("What is your Intial Velocity: "))  
        t = float(raw_input("What is the time: " )) 
        aa = v - u 
        answer = aa / t 
        print "Your Acceleration is: ", answer 
        return answer

a = formula.eq() 

print a

hyleaus · Answer 3 · 2013-11-28T21:11:01.630

0

try:

class formula(): 
def eq(self): 
    print "What is your Velocity: " 
    v = float(raw_input()) 
    print "What is your Intial Velocity: " 
    u = float(raw_input())  
    print "What is the time: " 
    t = float(raw_input()) 
    aa = v-u 
    answer = aa/t 
    print "Your Acceleration is: ", answer 

a = formula()
print a.eq()

edited Nov 28 '13 at 21:11

answered Nov 28 '13 at 21:03

hyleaus

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touche. didn't catch it. – hyleaus Nov 28 '13 at 21:09
Your indentation is now off. Note that `formula().eq()` returns `None`; the `print` is pretty useless here. – Martijn Pieters Nov 28 '13 at 21:17

Access a function from a class in Python?

3 Answers3