# How do I dot-assign to a returned value using \`@.\`?

**URL:** <https://discourse.julialang.org/t/how-do-i-dot-assign-to-a-returned-value-using/97683>\
**Category:** General Usage\
**Tags:** question\
**Created:** [April 19, 2023, 9:46pm UTC](https://discourse.julialang.org/t/how-do-i-dot-assign-to-a-returned-value-using/97683 "2023-04-19T21:46:39Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![Kino](https://avatars.discourse-cdn.com/v4/letter/k/65b543/32.png) [@Kino](https://discourse.julialang.org/u/Kino)\
**Post date:** [April 19, 2023, 9:46pm UTC](https://discourse.julialang.org/t/how-do-i-dot-assign-to-a-returned-value-using/97683/1 "2023-04-19T21:46:39Z")

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Let’s create 2 arrays first:

```julia
julia> a = rand(100); b = rand(100)

```

Take `identity(a)` as an example. These works:

- `identity(a) .= b`
- `identity(a) .+= b`
- `@. $identity(a) += b`
- `x = identity(a); @. x = b`

But this doesn’t:

```julia
julia> @. $identity(a) = b
ERROR: syntax: invalid function name "$identity" around REPL[69]:1

```

Seems that Julia thinks I’m defining a function called `$identity`.

---

<div class="post-metadata">

**Author:** ![olynch](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/olynch/32/17839_2.png) [@olynch](https://discourse.julialang.org/u/olynch)\
**Post date:** [April 19, 2023, 9:49pm UTC](https://discourse.julialang.org/t/how-do-i-dot-assign-to-a-returned-value-using/97683/2 "2023-04-19T21:49:57Z")

</div>

Try `@. $(identity(a)) = b`

---

<div class="post-metadata">

**Author:** ![Kino](https://avatars.discourse-cdn.com/v4/letter/k/65b543/32.png) [@Kino](https://discourse.julialang.org/u/Kino)\
**Post date:** [April 20, 2023, 2:34pm UTC](https://discourse.julialang.org/t/how-do-i-dot-assign-to-a-returned-value-using/97683/3 "2023-04-20T14:34:06Z")

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It works. Thanks!