# SubString and missing

**URL:** <https://discourse.julialang.org/t/substring-and-missing/79017>\
**Category:** New to Julia\
**Tags:** strings, missing-values\
**Created:** [April 4, 2022, 6:51pm UTC](https://discourse.julialang.org/t/substring-and-missing/79017 "2022-04-04T18:51:23Z")\
**Posts on this page:** 4\
**Page:** 1

<div class="post-metadata">

**Author:** ![gjh](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/gjh/32/31762_2.png) [@gjh](https://discourse.julialang.org/u/gjh)\
**Post date:** [April 4, 2022, 6:51pm UTC](https://discourse.julialang.org/t/substring-and-missing/79017/1 "2022-04-04T18:51:23Z")

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with this vector  
str = [“az”, “by”, missing, “cx”]

how can I get this returned using SubString?  
[“a”, “b”, missing, “c”]

Thank you!

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<div class="post-metadata">

**Author:** ![oheil](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/oheil/32/220745_2.png) [@oheil](https://discourse.julialang.org/u/oheil)\
**Post date:** [April 4, 2022, 7:00pm UTC](https://discourse.julialang.org/t/substring-and-missing/79017/2 "2022-04-04T19:00:29Z")

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For example:

```julia
julia> str = ["az", "by", missing, "cx"];

julia> [ismissing(x) ? missing : SubString(x,1,1) for x in str]
4-element Vector{Union{Missing, SubString{String}}}:
 "a"
 "b"
 missing
 "c"

```

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<div class="post-metadata">

**Author:** ![DNF](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/dnf/32/10191_2.png) [@DNF](https://discourse.julialang.org/u/DNF)\
**Post date:** [April 4, 2022, 7:17pm UTC](https://discourse.julialang.org/t/substring-and-missing/79017/3 "2022-04-04T19:17:08Z")

</div>

Not sure if you actually need a substring, but if you can use character instead, try replacing `SubString` with `first`.

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<div class="post-metadata">

**Author:** ![pdeffebach](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/pdeffebach/32/10320_2.png) [@pdeffebach](https://discourse.julialang.org/u/pdeffebach)\
**Post date:** [April 4, 2022, 7:25pm UTC](https://discourse.julialang.org/t/substring-and-missing/79017/4 "2022-04-04T19:25:03Z")

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Missings.jl has the function `passmissing`, so you would write

```julia
julia> str = ["az", "by", missing, "cx"];

julia> [passmissing(SubString)(x, 1, 1) for x in str]
4-element Vector{Union{Missing, SubString{String}}}:
 "a"
 "b"
 missing
 "c"

```