# define function on two sets

Hi. I have two sets: X, Y. I want to define a function

F : X ->Y

and I have the values of f(x). I searched the net but found nothing. thanks.

define function on two sets

**
asked 2017-11-10 09:53:26 +0200 **

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Hi. I have two sets: X, Y. I want to define a function

F : X ->Y

and I have the values of f(x). I searched the net but found nothing. thanks.

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Asked: ** 2017-11-10 09:53:26 +0200 **

Seen: **74 times**

Last updated: **Nov 10 '17**

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Your question is not very clear to me. I suppose that $X$ and $Y$ are finite sets. If you know a map from $X$ to $Y$ and you want to define it in SageMath, you may define a dictionary with keys $X$ and values $Y$ : define

`d = dict()`

and then`d[x] = y`

for all pairs $(x,y)$ such that $y = f(x)$. If on the other hand you have $f$ defined insomeway, such as a dictionary or something similar, and you want it truly as a function, you may write (I use the dictionary, known globally):Could you please provide the sets and the function you want to deal with in Sage ?