How to test for Indeterminate values?

Question

I need something like this

a = 101010/0;
If[a == ComplexInfinity, True, False]

But if I use ToString, I get what I want.

a = 101010/0;
If[ToString[a] == "ComplexInfinity", True, False]

Does someone know a better way to do this?, I can't belive that transforming to a string is the only way.

This question might be interesting for you Max of a table/list with indeterminate values. — Artes, Commented Sep 13, 2014 at 22:29
I think you want SameQ (===) i.e. If[a === ComplexInfinity, True, False] — RunnyKine, Commented Sep 13, 2014 at 22:30
The title says Indeterminate but the question shows only ComplexInfinity -- do you mean both symbols, or just one, or something else? — Michael E2, Commented Sep 13, 2014 at 23:19

2 revs · Accepted Answer · 2014-09-13 22:43:39Z

10

For the record, as RunnyKine wrote in a comment

a = 101010/0;
If[a === ComplexInfinity, True, False]

True

is what you are looking for.

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Basheer Algohi · Accepted Answer · 2014-09-13 22:53:30Z

2

you can also try:

a = 101010/0;
If[1/a == 0, True, False]

answered Sep 13, 2014 at 22:53

Basheer Algohi

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eldo · Accepted Answer · 2014-09-13 23:09:08Z

1

A generalization could look like this:

{1, 101010/0, 2, 0/0, Infinity, -Infinity} /.
   ComplexInfinity | DirectedInfinity | Indeterminate :> True /. True[1 | -1] -> True

{1, True, 2, True, True, True}

answered Sep 13, 2014 at 23:09

eldo

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$\begingroup$ Or ... /. ComplexInfinity | DirectedInfinity[1] | DirectedInfinity[-1] | Indeterminate :> True $\endgroup$
– Bob Hanlon
Commented Sep 14, 2014 at 0:02

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3 Answers 3