# Conversion isna.(DataArray) to BitArray

**URL:** https://discourse.julialang.org/t/conversion-isna-dataarray-to-bitarray/6078
**Category:** General Usage
**Created:** [September 26, 2017, 9:02am UTC](https://discourse.julialang.org/t/conversion-isna-dataarray-to-bitarray/6078 "2017-09-26T09:02:38Z")
**Posts on this page:** 3
**Page:** 1

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### Author: ![abieler](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/abieler/32/2693_2.png) [@abieler](https://discourse.julialang.org/u/abieler)
#### Post date: [September 26, 2017, 9:02am UTC](https://discourse.julialang.org/t/conversion-isna-dataarray-to-bitarray/6078/1 "2017-09-26T09:02:38Z")

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Can someone explain the difference between the two examples below:  
(Julia v0.6 and DataFrames 0.10.1)

```julia
flt = isna.(mydataframe[:var]) # -> BitArray{1}
inv_flt = .!(flt) # -> BitArray{1}

# however...
inv_flt = .!(isna.(mydataframe[:var])) # --> DataArray{Any, 1}

```

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<div class="post-metadata">

### Author: ![pfitzseb](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/pfitzseb/32/45566_2.png) [@pfitzseb](https://discourse.julialang.org/u/pfitzseb)
#### Post date: [September 26, 2017, 9:44am UTC](https://discourse.julialang.org/t/conversion-isna-dataarray-to-bitarray/6078/2 "2017-09-26T09:44:13Z")

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Try

```julia
inv_flt = .!(isna.(mydataframe[:var]))

```

(and note the additional `.` after `isna`).

---

<div class="post-metadata">

### Author: ![abieler](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/abieler/32/2693_2.png) [@abieler](https://discourse.julialang.org/u/abieler)
#### Post date: [September 26, 2017, 9:57am UTC](https://discourse.julialang.org/t/conversion-isna-dataarray-to-bitarray/6078/3 "2017-09-26T09:57:08Z")

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Sorry that was a typo. What I actually have in my code is what you describe with the additional dot.  
I now edited my post above, the question remains