# How to extract first arguments from dictionaries in Julia?
**URL:** https://discourse.julialang.org/t/how-to-extract-first-arguments-from-dictionaries-in-julia/103653
**Category:** New to Julia
**Created:** [September 8, 2023, 9:17am UTC](https://discourse.julialang.org/t/how-to-extract-first-arguments-from-dictionaries-in-julia/103653 "2023-09-08T09:17:48Z")
**Posts on this page:** 4
**Page:** 1
### Author:  [@Luigi\_Marongiu](https://discourse.julialang.org/u/Luigi_Marongiu)
#### Post date: [September 8, 2023, 9:17am UTC](https://discourse.julialang.org/t/how-to-extract-first-arguments-from-dictionaries-in-julia/103653/1 "2023-09-08T09:17:48Z")
Hello,
this is a basic question but I am not familiar with dictionaries, preferring arrays. I have set a dictionary as
```julia
julia> D = Dict("Field_1"=>[1,2,3,4,5],
"Field_2"=>["a", "b", "c", "d", "e"])
Dict{String, Vector} with 2 entries:
"Field_1" => [1, 2, 3, 4, 5]
"Field_2" => ["a", "b", "c", "d", "e"]
```
What is the function to assess how many entries are in it? That is, I should get a `n = 5` somehow?
Also, it is possible to extract the first entry of each field and assign it to a different array?
That is, if I reiterate between 1 and n, can I do something like:
```julia
d = ["Field_1" [1], "Field_2" [a]]
A = d[1]
B = d[2]
```
Thank you
---
### Author:  [@nilshg](https://discourse.julialang.org/u/nilshg)
#### Post date: [September 8, 2023, 9:36am UTC](https://discourse.julialang.org/t/how-to-extract-first-arguments-from-dictionaries-in-julia/103653/2 "2023-09-08T09:36:21Z")
> [@Luigi\_Marongiu](#):
>
> What is the function to assess how many entries are in it? That is, I should get a `n = 5` somehow?
By “it” do you mean the arrays stored as the values in the dictionary? A dictionary is made up of `(key, value)` pairs:
```julia
julia> for (k, v) ∈ pairs(D)
println("Key: ", k, " value: ", v)
end
Key: Field_1 value: [1, 2, 3, 4, 5]
Key: Field_2 value: ["a", "b", "c", "d", "e"]
```
So if you want to check the number of entries in each array you can do:
```julia
julia> length.(values(D))
2-element Vector{Int64}:
5
5
```
I’m afraid I don’t understand the second question. The first element of each array in your dict is accessed in the same way as computing the length above:
```julia
julia> first.(values(D))
2-element Vector{Any}:
1
"a"
```
---
### Author:  [@mike\_k](https://discourse.julialang.org/u/mike_k)
#### Post date: [September 8, 2023, 9:36am UTC](https://discourse.julialang.org/t/how-to-extract-first-arguments-from-dictionaries-in-julia/103653/3 "2023-09-08T09:36:33Z")
You could use, e.g., `length(D["Field_1"])` to obtain the length of the array in Field\_1, and `first(D["Field_1"])` to obtain the first element.
---
### Author:  [@Luigi\_Marongiu](https://discourse.julialang.org/u/Luigi_Marongiu)
#### Post date: [September 8, 2023, 1:09pm UTC](https://discourse.julialang.org/t/how-to-extract-first-arguments-from-dictionaries-in-julia/103653/4 "2023-09-08T13:09:07Z")
> [@nilshg](#):
>
> ```julia
> for (k, v) ∈ pairs(D)
> println("Key: ", k, " value: ", v)
> end
>
> ```
Thank you. `k` and `v` extract the data exactly as needed. `length` gives me also the information I needed.