How to add multivariable functions in python

Question

May I know how should I add two functions(Multivariable).
For example,

T=lambda t,y: [0,t] 
P=lambda t,y: [y,y]

what is the proper way to get T-P because when I tried, it gives an error message
"unsupported operand type(s) for -: 'function' and 'function'".

At first I mulitvariable case will also follow the same case as it is for single variable. (here) but it doesn't work.

And I apologize for putting my question as a single variable function earlier

Does this answer your question? [How to combine two lambda functions into one?](https://stackoverflow.com/questions/43806354/how-to-combine-two-lambda-functions-into-one) — Avishka Dambawinna, Apr 21 '20 at 17:07
I don't know what you trying to archive, but you can do this also `f = lambda x, y: x**2+y**3` and pass two parameters to **x** and **y** , `f(2,2)` — Avishka Dambawinna, Apr 21 '20 at 17:23
Thank you for the comment @AvishkaDambawinna .. What I really need to do is: I have two multivariable functions `T=lambda t,y: [0,t]` and `P=lambda t,y: [y,y]` And I need to have a third function that gets the addition of T and P. But seems like it dosen't work — Charith, Apr 21 '20 at 17:32
What do you mean by minus for lists `[0,t]` and `[y,y]`? Can you provide the desired behavior for the function `T-P`? — Fomalhaut, Apr 21 '20 at 19:58

Fomalhaut · Answer 1 · 2020-04-21T17:15:55.153

2

Try this:

f = lambda x: f1(x) + f2(x)

If you want to add functions with arbitrary arguments you can define a solution like this:

def add_functions(f1, f2):
    def f(*args, **kwargs):
        return f1(*args, **kwargs) + f2(*args, **kwargs)
    return f

edited Apr 21 '20 at 17:15

answered Apr 21 '20 at 16:55

Fomalhaut

8,590
8
51
95

I see. Thank you very much. Your first suggestion would do my job. Anyway can you tell me what does *args and **kwargs means – Charith Apr 21 '20 at 17:08
1

You are welcome. You can read about it here: https://stackoverflow.com/questions/36901/what-does-double-star-asterisk-and-star-asterisk-do-for-parameters – Fomalhaut Apr 21 '20 at 17:11
What I really needed to do is: I have two multivariable functions `T=lambda t,y: [0,t]` and `P=lambda t,y: [y,y]` And I want to have a third function that gets the addition of T and P. But seems like it dosen't work – Charith Apr 21 '20 at 17:40
Can you, please, update your question give the certain result you expect from the addition of the functions? – Fomalhaut Apr 21 '20 at 17:43

score 0 · Answer 2 · answered Aug 25 '21 at 16:54

0

f = lambda x, y: x + y
# f(2, 3) = 2 + 3 = 5 
g = lambda x, y: x * y
# g(2, 3) = 2 * 3 = 6 
h = lambda x, y: f(x, y) + g(x, y)
# h(2, 3) = f(2, 3) + g(2, 3) = (2 + 3) + (2 * 3) = 5 + 6 = 11

answered Aug 25 '21 at 16:54

J Doe

1

4

Welcome to Stack Overflow. Please edit your answer and explain how it answers the specific question being asked. Stack Overflow is about learning, not providing snippets to blindly copy and paste. See How to Answer. https://stackoverflow.com/help/how-to-answer – cards Aug 25 '21 at 21:50

score -1 · Answer 3 · answered Apr 21 '20 at 16:58

-1

If I understand your problem, I guess the only way would be a third function.
Like this:

f3 = lambda x,y: f1(x) + f2(y)

answered Apr 21 '20 at 16:58

axolotl

93
6

How to add multivariable functions in python

3 Answers3