# Return of split
**URL:** https://discourse.julialang.org/t/return-of-split/122987
**Category:** New to Julia
**Tags:** function
**Created:** [November 23, 2024, 10:17am UTC](https://discourse.julialang.org/t/return-of-split/122987 "2024-11-23T10:17:22Z")
**Posts on this page:** 7
**Page:** 1
### Author:  [@martin\_sanchez](https://discourse.julialang.org/u/martin_sanchez)
#### Post date: [November 23, 2024, 10:17am UTC](https://discourse.julialang.org/t/return-of-split/122987/1 "2024-11-23T10:17:22Z")
I was using split(str,separator) and it returned SubString (I verified it with typeof) and wa using the result in later functions:
```julia
function instruct_processor(db::Dict,op::String)
arr=split(op," ",limit=2)
print("primer arr: ")
println(typeof(arr))
```
and suddenly it returns a vector of substrings:
```julia
Vector{SubString{String}}
```
But what really intrigues me is that even though I was receiving an error
Because of this function:
```julia
function _long_adecuada(len::Integer,arr::Vector{SubString{String}})
length(arr)!=len && throw(NumberArgsError())
end
```
```julia
ERROR: LoadError: MethodError: no method matching _long_adecuada(::Int64, ::Vector{SubString{String}})
Closest candidates are:
_long_adecuada(::Integer, ::SubString{String})
```
The other functions that also received Substring did not show error:
This runs:
````julia
type or paste code here
```function insertField!(db::Dict,params::SubString{String})
typeof(params)
arr=split(params," ",limit=3)
println(typeof(arr))
println(length(arr))
````
---
### Author:  [@nsajko](https://discourse.julialang.org/u/nsajko)
#### Post date: [November 23, 2024, 10:26am UTC](https://discourse.julialang.org/t/return-of-split/122987/2 "2024-11-23T10:26:06Z")
> [@martin\_sanchez](#):
>
> I was using split(str,separator) and it returned SubString
For example? (Give minimal reproducer.)
---
### Author:  [@DanielVandH](https://discourse.julialang.org/u/DanielVandH)
#### Post date: [November 23, 2024, 10:30am UTC](https://discourse.julialang.org/t/return-of-split/122987/3 "2024-11-23T10:30:41Z")
Please see the post [Please read: make it easier to help you](https://discourse.julialang.org/t/please-read-make-it-easier-to-help-you/14757). It will make it easier to help with your questions.
---
### Author:  [@GunnarFarneback](https://discourse.julialang.org/u/GunnarFarneback)
#### Post date: [November 23, 2024, 11:02am UTC](https://discourse.julialang.org/t/return-of-split/122987/4 "2024-11-23T11:02:17Z")
It’s hard to follow what you did and what works or not for you but the docstring for `split` says
> Split str into an array of substrings
so focus on showing how to reproduce
> I was using split(str,separator) and it returned SubString
and we can tell you whether there is some misunderstanding or you have found a bug.
---
### Author:  [@bertschi](https://discourse.julialang.org/u/bertschi)
#### Post date: [November 23, 2024, 11:07am UTC](https://discourse.julialang.org/t/return-of-split/122987/5 "2024-11-23T11:07:44Z")
A substring is like a view into a string, i.e., references into an existing string instead of allocating a new data structure. Many functions for splitting, matching etc on strings return substrings. Here is an example:
```julia-repl
julia> txt = "Hi there"
"Hi there"
julia> sub = match(r"Hi", txt).match
"Hi"
julia> typeof(sub)
SubString{String}
julia> parent(sub) # The underlying original string
"Hi there"
julia> split(txt, " ")
2-element Vector{SubString{String}}:
"Hi"
"there"
julia> parent.(split(txt, " "))
2-element Vector{String}:
"Hi there"
"Hi there"
```
Note that a `SubString` is not a `String`, i.e., a function with signature `op::String` will not work as expected:
```julia-repl
julia> fun(op::String) = length(op)
fun (generic function with 1 method)
julia> fun(txt)
8
julia> fun(sub)
ERROR: MethodError: no method matching fun(::SubString{String})
```
If in doubt, leave out the type signature all together (would suggest that for beginners anyways) or use `AbstractString` instead which will match all of its subtypes:
```julia-repl
julia> subtypes(AbstractString)
6-element Vector{Any}:
Base.AnnotatedString
Core.Compiler.LazyString
LazyString
String
SubString
SubstitutionString
```
---
### Author:  [@GunnarFarneback](https://discourse.julialang.org/u/GunnarFarneback)
#### Post date: [November 23, 2024, 11:30am UTC](https://discourse.julialang.org/t/return-of-split/122987/7 "2024-11-23T11:30:42Z")
I don’t see anything surprising there.
> `arr=split(op," ",limit=2)`
gives you `arr` as a `Vector{SubString{String}}`.
Then `arr[2]` extracts one element from the vector which gives you a `SubString{String}`. When you send that single element to `insertField!` it complains because it requires a whole vector, not a single element.
---
### Author:  [@bertschi](https://discourse.julialang.org/u/bertschi)
#### Post date: [November 23, 2024, 11:34am UTC](https://discourse.julialang.org/t/return-of-split/122987/8 "2024-11-23T11:34:21Z")
The error says that `insertField!` expected a vector in its second argument (as per your type signature `Vector{SubString{String}}`), but was called with a `SubString{String}`, i.e., as single element of such a vector. Have not checked if this function actually needs to get passed a vector – but as `split` is called on `params` it most likely does not.
In any case, such a specific type signature usually restricts code unnecessarily. Consider `AbstractVector{<:AbstractString}` instead.