# Word for !isnan

**URL:** <https://discourse.julialang.org/t/word-for-isnan/91803>\
**Category:** Offtopic\
**Created:** [December 18, 2022, 4:43am UTC](https://discourse.julialang.org/t/word-for-isnan/91803 "2022-12-18T04:43:09Z")\
**Posts on this page:** 5\
**Page:** 1

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**Author:** ![jar1](https://avatars.discourse-cdn.com/v4/letter/j/c0e974/32.png) [@jar1](https://discourse.julialang.org/u/jar1)\
**Post date:** [December 18, 2022, 4:43am UTC](https://discourse.julialang.org/t/word-for-isnan/91803/1 "2022-12-18T04:43:09Z")

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Is there a a technical (but not necessarily Julia) word for values that aren’t nan?

(Edited)

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**Author:** ![stillyslalom](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/stillyslalom/32/45687_2.png) [@stillyslalom](https://discourse.julialang.org/u/stillyslalom)\
**Post date:** [December 18, 2022, 5:22am UTC](https://discourse.julialang.org/t/word-for-isnan/91803/3 "2022-12-18T05:22:58Z")

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The nearest Julia idiom is `isfinite`, which also excludes `Inf`/`-Inf`. There’s always this route, too:

```julia
julia> isan = !isnan
#97 (generic function with 1 method)

julia> isan(3)
true

julia> isan(NaN)
false

```

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<div class="post-metadata">

**Author:** ![mcreel](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/mcreel/32/30088_2.png) [@mcreel](https://discourse.julialang.org/u/mcreel)\
**Post date:** [December 18, 2022, 9:00am UTC](https://discourse.julialang.org/t/word-for-isnan/91803/4 "2022-12-18T09:00:39Z")

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Not not a number is a number, no?

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**Author:** ![mezzarobba](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/mezzarobba/32/45191_2.png) [@mezzarobba](https://discourse.julialang.org/u/mezzarobba)\
**Post date:** [December 18, 2022, 10:47am UTC](https://discourse.julialang.org/t/word-for-isnan/91803/5 "2022-12-18T10:47:04Z")

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IEEE 754 simply calls it a “floating-point number” (and uses “floating-point datum” for something that may be a floating point number or a NaN).

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**Author:** ![jules](https://avatars.discourse-cdn.com/v4/letter/j/41988e/32.png) [@jules](https://discourse.julialang.org/u/jules)\
**Post date:** [December 18, 2022, 11:13am UTC](https://discourse.julialang.org/t/word-for-isnan/91803/6 "2022-12-18T11:13:29Z")

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I would use `non_nan` or `not_nan` maybe. People aren’t good at double negatives and I’d argue almost nobody thinks “this is not a number” but “this is a NaN value” so the meaning is positive while the derivation is negative.