# Which to prefer in simple cases, \`map!\` or \`broadcast!\`
**URL:** https://discourse.julialang.org/t/which-to-prefer-in-simple-cases-map-or-broadcast/11415
**Category:** General Usage
**Created:** [June 4, 2018, 3:13pm UTC](https://discourse.julialang.org/t/which-to-prefer-in-simple-cases-map-or-broadcast/11415 "2018-06-04T15:13:22Z")
**Posts on this page:** 4
**Page:** 1
### Author:  [@dmbates](https://discourse.julialang.org/u/dmbates)
#### Post date: [June 4, 2018, 3:13pm UTC](https://discourse.julialang.org/t/which-to-prefer-in-simple-cases-map-or-broadcast/11415/1 "2018-06-04T15:13:22Z")
In a simple case, such as
```julia
v = collect(1:10)
sqrs = similar(v)
map!(abs2, sqrs, v)
```
would it be better to use `broadcast!`? I am using the `!` form (instead of a `.=` assignment) because this expression could be part of a larger expression. My guess is that `broadcast!` could be preferred if there was a chance that it could be fused with other operations.
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### Author:  [@Nosferican](https://discourse.julialang.org/u/Nosferican)
#### Post date: [June 4, 2018, 8:51pm UTC](https://discourse.julialang.org/t/which-to-prefer-in-simple-cases-map-or-broadcast/11415/2 "2018-06-04T20:51:24Z")
I would agree with your guess.
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### Author:  [@ExpandingMan](https://discourse.julialang.org/u/ExpandingMan)
#### Post date: [June 4, 2018, 8:53pm UTC](https://discourse.julialang.org/t/which-to-prefer-in-simple-cases-map-or-broadcast/11415/3 "2018-06-04T20:53:16Z")
My understanding is that `broadcast` is for `AbstractArray`s and that `map` is for general collections. So, roughly speaking, if your collection has a well-defined order, use `broadcast`. In other cases (e.g. `Set` or `Dict`), use `map`.
So, in your case I would agree: `broadcast`.
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### Author:  [@mbauman](https://discourse.julialang.org/u/mbauman)
#### Post date: [June 4, 2018, 9:05pm UTC](https://discourse.julialang.org/t/which-to-prefer-in-simple-cases-map-or-broadcast/11415/4 "2018-06-04T21:05:27Z")
`map!` and `broadcast!` are indeed basically the same for these one-argument cases. They only way you’ll see a difference is if a type specifically specialized one but not the other — and then it can only ever be a difference in performance. Broadcasting does have the big advantage of fusion.
You’re more likely to see a difference between the non-bang `map` and `broadcast` since they have a very different system of allocating the resulting array: the former uses `similar` for `AbstractArray`s whereas the latter uses broadcast styles.