# NamedTuple, how to assign values?
**URL:** https://discourse.julialang.org/t/namedtuple-how-to-assign-values/78933
**Category:** New to Julia
**Tags:** namedtuple
**Created:** [April 3, 2022, 7:47am UTC](https://discourse.julialang.org/t/namedtuple-how-to-assign-values/78933 "2022-04-03T07:47:24Z")
**Posts on this page:** 5
**Page:** 1
### Author:  [@Ahmed\_Salih](https://discourse.julialang.org/u/Ahmed_Salih)
#### Post date: [April 3, 2022, 7:47am UTC](https://discourse.julialang.org/t/namedtuple-how-to-assign-values/78933/1 "2022-04-03T07:47:24Z")
Hello!
Suppose I have a line as such:
```julia
varNames = NamedTuple{(:key,:offset,:type,:ncol), Tuple{String,Int,DataType,Int}}
```
The typeof this is:
```julia
typeof(varNames)
DataType
```
Then my question is; how do I insert values into, i.e. construct a NamedTuple based on this data type?
Kind regards
---
### Author:  [@gustaphe](https://discourse.julialang.org/u/gustaphe)
#### Post date: [April 3, 2022, 8:25am UTC](https://discourse.julialang.org/t/namedtuple-how-to-assign-values/78933/2 "2022-04-03T08:25:26Z")
I don’t know why you want to do this, you’re probably looking for a `struct`.
That said,
```julia
julia> varNames(("hi",3,String,4))
(key = "hi", offset = 3, type = String, ncol = 4)
```
---
### Author:  [@Ahmed\_Salih](https://discourse.julialang.org/u/Ahmed_Salih)
#### Post date: [April 3, 2022, 9:05am UTC](https://discourse.julialang.org/t/namedtuple-how-to-assign-values/78933/3 "2022-04-03T09:05:33Z")
Thanks!
I ended up doing it differently this time as you hinted at (dict, instead of struct), but knowledge is power, so thanks for sharing the correct way to do it! 😊
Kind regards
---
### Author:  [@gustaphe](https://discourse.julialang.org/u/gustaphe)
#### Post date: [April 3, 2022, 9:14am UTC](https://discourse.julialang.org/t/namedtuple-how-to-assign-values/78933/4 "2022-04-03T09:14:37Z")
That’s probably fine. Just wanted to point out that there are many advantages to a struct over a Dict for something like this, performance wise.
```julia
struct VarNames
key::String
offset::Int
type::DataType
ncol::Int
end
```
It gives you dispatch, clearer contract and more efficient storage than a `Dict{Symbol, Any}`. If you’re willing to void the dispatch you could have also just used a `NamedTuple` like you first suggested, but without the intermediate type alias:
```julia
x = (key="hi", offset=3, type=String, ncol=4)
```
But if it works it works.
---
### Author:  [@sylvaticus](https://discourse.julialang.org/u/sylvaticus)
#### Post date: [April 3, 2022, 11:05am UTC](https://discourse.julialang.org/t/namedtuple-how-to-assign-values/78933/5 "2022-04-03T11:05:10Z")
You can’t insert values in a NamedTuple (or a Tuple for what does it matter), as these are _immutable_ types, after they have been created you can’t modify them (you can still modify -but not reassign - mutable elements of it)