# Isupercase with String Array how tu use?
**URL:** https://discourse.julialang.org/t/isupercase-with-string-array-how-tu-use/22870
**Category:** General Usage
**Created:** [April 7, 2019, 2:07pm UTC](https://discourse.julialang.org/t/isupercase-with-string-array-how-tu-use/22870 "2019-04-07T14:07:41Z")
**Posts on this page:** 12
**Page:** 1
### Author:  [@programista](https://discourse.julialang.org/u/programista)
#### Post date: [April 7, 2019, 2:07pm UTC](https://discourse.julialang.org/t/isupercase-with-string-array-how-tu-use/22870/1 "2019-04-07T14:07:41Z")
isupercase with String Array how tu use ? How to convet Array a to Array of Char?
> julia\> a
> 3-element Array{String,1}:
> “a”
> “5”
> “A”
>
> julia\> isuppercase.(a)
> ERROR: MethodError: no method matching isuppercase(::String)
> Closest candidates are:
> isuppercase(::AbstractChar) at strings/unicode.jl:313
> Stacktrace:
> [1] \_broadcast\_getindex\_evalf at .\broadcast.jl:574 [inlined]
> [2] \_broadcast\_getindex at .\broadcast.jl:547 [inlined]
> [3] getindex at .\broadcast.jl:507 [inlined]
> [4] copy at .\broadcast.jl:758 [inlined]
> [5] materialize(::Base.Broadcast.Broadcasted{Base.Broadcast.DefaultArrayStyle{1},Nothing,typeof(isuppercase),Tuple{Array{String,1}}}) at .\broadcast.jl:724
> [6] top-level scope at none:0
> Paul
---
### Author:  [@JeffreySarnoff](https://discourse.julialang.org/u/JeffreySarnoff)
#### Post date: [April 7, 2019, 2:22pm UTC](https://discourse.julialang.org/t/isupercase-with-string-array-how-tu-use/22870/3 "2019-04-07T14:22:14Z")
`[s[1] for s in a]`
`isuppercase.([s[1] for s in a])`
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### Author:  [@DNF](https://discourse.julialang.org/u/DNF)
#### Post date: [April 7, 2019, 2:33pm UTC](https://discourse.julialang.org/t/isupercase-with-string-array-how-tu-use/22870/4 "2019-04-07T14:33:22Z")
Won’t this fail for unicode characters with lengths longer than 1? Not at my computer now, but how about `isuppercase.(first.(a))`?
Are all the strings guaranteed to consist of a single character?
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### Author:  [@JeffreySarnoff](https://discourse.julialang.org/u/JeffreySarnoff)
#### Post date: [April 7, 2019, 2:40pm UTC](https://discourse.julialang.org/t/isupercase-with-string-array-how-tu-use/22870/5 "2019-04-07T14:40:56Z")
`first` looks good to me. Although I think the index [1] works too (because its `1`). I have no info about the string’s charcount.
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### Author:  [@programista](https://discourse.julialang.org/u/programista)
#### Post date: [April 7, 2019, 2:43pm UTC](https://discourse.julialang.org/t/isupercase-with-string-array-how-tu-use/22870/6 "2019-04-07T14:43:28Z")
Thanks , and one more ~!
[a[i] not works
[a[i][1] this works :
> julia\> isuppercase.([a[i][1] for i=1:length(a)])
> 3-element BitArray{1}:
> false
> false
> true
Paul
---
### Author:  [@JeffreySarnoff](https://discourse.julialang.org/u/JeffreySarnoff)
#### Post date: [April 7, 2019, 2:45pm UTC](https://discourse.julialang.org/t/isupercase-with-string-array-how-tu-use/22870/7 "2019-04-07T14:45:05Z")
Its `firstindex` rather than `first`.
---
### Author:  [@DNF](https://discourse.julialang.org/u/DNF)
#### Post date: [April 7, 2019, 3:03pm UTC](https://discourse.julialang.org/t/isupercase-with-string-array-how-tu-use/22870/8 "2019-04-07T15:03:33Z")
I’m a bit surprised by the performance here:
```julia
julia> a = ["a", "5", "A"]
julia> @btime [isuppercase(first(s)) for s in $a]
79.761 ns (2 allocations: 112 bytes)
3-element Array{Bool,1}:
false
false
true
julia> @btime isuppercase.(first.($a))
433.894 ns (3 allocations: 4.31 KiB)
3-element BitArray{1}:
false
false
true
```
---
### Author:  [@JeffreySarnoff](https://discourse.julialang.org/u/JeffreySarnoff)
#### Post date: [April 7, 2019, 3:07pm UTC](https://discourse.julialang.org/t/isupercase-with-string-array-how-tu-use/22870/9 "2019-04-07T15:07:07Z")
The second is allocating much, much more memory.
---
### Author:  [@DNF](https://discourse.julialang.org/u/DNF)
#### Post date: [April 7, 2019, 3:07pm UTC](https://discourse.julialang.org/t/isupercase-with-string-array-how-tu-use/22870/10 "2019-04-07T15:07:40Z")
Yes, but it shouldn’t, as far as I can tell.
---
### Author:  [@JeffreySarnoff](https://discourse.julialang.org/u/JeffreySarnoff)
#### Post date: [April 7, 2019, 3:10pm UTC](https://discourse.julialang.org/t/isupercase-with-string-array-how-tu-use/22870/11 "2019-04-07T15:10:00Z")
The glitch is in broadcasting `isuppercase`. With `map` instead of broadcast, its fast again.
```julia
julia> @btime map(isuppercase,first.($a))
72.614 ns (3 allocations: 208 bytes)
julia> @btime isuppercase.(first.($a))
326.126 ns (3 allocations: 4.31 KiB)
```
---
### Author:  [@DNF](https://discourse.julialang.org/u/DNF)
#### Post date: [April 7, 2019, 3:16pm UTC](https://discourse.julialang.org/t/isupercase-with-string-array-how-tu-use/22870/12 "2019-04-07T15:16:50Z")
> [@JeffreySarnoff](#):
>
> `map(isuppercase,first.($a))`
Seems to me that there is some issue when a `BitArray` is produced instead of a `Vector{Bool}`. I can see the same thing here:
```julia
julia> foo(x, val) = x .> val
julia> bar(x, val) = [y > val for y in x]
julia> @btime foo(1:7, 3)
397.475 ns (3 allocations: 4.31 KiB)
7-element BitArray{1}:
false
false
false
true
true
true
true
julia> @btime bar(1:7, 3)
39.051 ns (1 allocation: 96 bytes)
7-element Array{Bool,1}:
false
false
false
true
true
true
true
```
A _lot_ of allocations with `BitArray`.
---
### Author:  [@JeffreySarnoff](https://discourse.julialang.org/u/JeffreySarnoff)
#### Post date: [April 7, 2019, 3:18pm UTC](https://discourse.julialang.org/t/isupercase-with-string-array-how-tu-use/22870/13 "2019-04-07T15:18:01Z")
hmm … seems like you are on to something!