# Question: Function not returning a value?
**URL:** https://discourse.julialang.org/t/question-function-not-returning-a-value/71590
**Category:** General Usage
**Created:** [November 16, 2021, 2:29pm UTC](https://discourse.julialang.org/t/question-function-not-returning-a-value/71590 "2021-11-16T14:29:42Z")
**Posts on this page:** 10
**Page:** 1
### Author:  [@mdhe1248](https://discourse.julialang.org/u/mdhe1248)
#### Post date: [November 16, 2021, 2:29pm UTC](https://discourse.julialang.org/t/question-function-not-returning-a-value/71590/1 "2021-11-16T14:29:43Z")
Could anyone help with this function? I would like to get a return value, but it returns nothing. The below is my function:
```nohighlight
function retrieve(dict, key_of_interest, value_of_interest)
for (key, value) in dict
if key == key_of_interest && value == value_of_interest
@show dict["name"] #just to check
return(dict["name"])
end
if value isa Vector
for child in value
retrieve(child, key_of_interest, value_of_interest)
end
end
end
end
```
```nohighlight
dict = Dict("id" => 1, "name" => "name1", "children" => [Dict("id" => 2, "name" => "name2", "children" => [], ), Dict("id" =>3, "name" => "name3", "children" => [])])
```
`dict` contains `id` and `children`, a vector of Dictionary. Each `children` would repeatedly contain a vector of Dictionary; but here in this sample example, I made it short.
```nohighlight
retrieve(dict, "id", 1) # It returns a value
retrieve(dict, "id", 2) # It does not return a value
```
I would like to get “name2” from `retrieve(dict, "id", 2)`. Could anyone explain why it returns `Nothing` and guide me how to solve this?
---
### Author:  [@John\_Gibson](https://discourse.julialang.org/u/John_Gibson)
#### Post date: [November 16, 2021, 2:40pm UTC](https://discourse.julialang.org/t/question-function-not-returning-a-value/71590/2 "2021-11-16T14:40:35Z")
Though I haven’t worked your code in detail, I’m pretty sure what’s happening is you iterate through the `for (key, value)` loop without ever hitting a `return` statement. Eventually you get through the last iterate, (maybe get `false` for both `if` statements), and reach the final `end` for the function definition. Since the last statement executed was the `for` loop, its value `nothing` is returned by your function.
---
### Author:  [@John\_Gibson](https://discourse.julialang.org/u/John_Gibson)
#### Post date: [November 16, 2021, 2:45pm UTC](https://discourse.julialang.org/t/question-function-not-returning-a-value/71590/3 "2021-11-16T14:45:44Z")
I think there’s got to be a better tree structure available than coding one with nested Dicts.
---
### Author:  [@owiecc](https://discourse.julialang.org/u/owiecc)
#### Post date: [November 16, 2021, 2:46pm UTC](https://discourse.julialang.org/t/question-function-not-returning-a-value/71590/4 "2021-11-16T14:46:35Z")
The offending code here is `for child in value` where the last iteration does not return anything.
Ideally you’d want to convert this data structure to a tree so that you can use iterators to look for stuff more easily.
---
### Author:  [@owiecc](https://discourse.julialang.org/u/owiecc)
#### Post date: [November 16, 2021, 2:51pm UTC](https://discourse.julialang.org/t/question-function-not-returning-a-value/71590/5 "2021-11-16T14:51:05Z")
And if you know the value of interest then just return it 😉
```julia
retrieve(dict, key_of_interest, value_of_interest) = value_of_interest
```
---
### Author:  [@mdhe1248](https://discourse.julialang.org/u/mdhe1248)
#### Post date: [November 16, 2021, 3:22pm UTC](https://discourse.julialang.org/t/question-function-not-returning-a-value/71590/7 "2021-11-16T15:22:42Z")
Ah, I actually made things simple to solve this issue and forgot the original purpose of this function. There is another `key` that I want to return. I will update the original post in a couple of minutes.
---
### Author:  [@Jeff\_Emanuel](https://discourse.julialang.org/u/Jeff_Emanuel)
#### Post date: [November 16, 2021, 3:30pm UTC](https://discourse.julialang.org/t/question-function-not-returning-a-value/71590/9 "2021-11-16T15:30:40Z")
Use JSON3. It will decode into your own structs.
---
### Author:  [@mdhe1248](https://discourse.julialang.org/u/mdhe1248)
#### Post date: [November 16, 2021, 8:49pm UTC](https://discourse.julialang.org/t/question-function-not-returning-a-value/71590/10 "2021-11-16T20:49:13Z")
I solved the issue. The main problem was the fact that I thought whenever I called `return` in a nested function, the entire function would finish…haha. Thank you @owiecc and John\_Gibson for comments from where I was able to start tackling the issue. I did not carefully look into tree structure; and @Jeff_Emanuel, with JSON3 I couldn’t figure out how to load JSON as a tree structure. If anyone gives me how to convert nested Dictionary (potentially from a JSON file) into a tree, it will be great. Anyway my new function contains new three lines:
```nohighlight
function retrieve(dict, key_of_interest, value_of_interest)
for (key, value) in dict
if key == key_of_interest && value == value_of_interest
return(dict["name"])
end
if value isa Vector
for dict in value
label = retrieve(dict, key_of_interest, value_of_interest)
if !isnothing(label) #
return(label) # return value here.
end #
end
end
end
end
```
Of course, there might be potential issues. One would be the case where a downstream nested Dictionary contains the same “id”. In such a case, the “name” of the downstream Dictionary will not be retrieved.
---
### Author:  [@Jeff\_Emanuel](https://discourse.julialang.org/u/Jeff_Emanuel)
#### Post date: [November 17, 2021, 12:32am UTC](https://discourse.julialang.org/t/question-function-not-returning-a-value/71590/11 "2021-11-17T00:32:52Z")
```julia
struct Node
id
name
children::Vector{Node}
end
js = "{\"name\":\"name1\",\"id\":1,\"children\":[{\"name\":\"name2\",\"id\":2,\"children\":[]},{\"name\":\"name3\",\"id\":3,\"children\":[]}]}"
using JSON3, StructTypes
StructTypes.StructType(::Type{Node}) = StructTypes.Struct()
tree = JSON3.read(js,Node)
println(tree)
```
```julia
Node(1, "name1", Node[Node(2, "name2", Node[]), Node(3, "name3", Node[])])
```
---
### Author:  [@mdhe1248](https://discourse.julialang.org/u/mdhe1248)
#### Post date: [November 17, 2021, 3:38am UTC](https://discourse.julialang.org/t/question-function-not-returning-a-value/71590/12 "2021-11-17T03:38:39Z")
Thank you. I will try: I will need some time to get into a tree structure and how to manage it, and this seems a good starting point.