# polynomial ring instance check

Hi there, folks. How do i check if something is an instance of a polynomial ring (univariate or multivariate)?

polynomial ring instance check

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2

First of all, do you really need to? Just allow any input, if it does not have the methods you are calling then you will get a suitable `AttributeError`

exception thrown. AKA duck-typing.

If you are sure that you actually have to check the type, use the convenience functions:

```
sage: from sage.rings.polynomial.polynomial_ring import is_PolynomialRing
sage: is_PolynomialRing('string')
False
sage: from sage.rings.polynomial.multi_polynomial_ring import is_MPolynomialRing
sage: is_MPolynomialRing('string')
False
```

Asked: **
2012-01-18 10:32:10 -0500
**

Seen: **128 times**

Last updated: **Jan 18 '12**

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