# Column wise broadcast for a matrix
**URL:** https://discourse.julialang.org/t/column-wise-broadcast-for-a-matrix/11113
**Category:** New to Julia
**Created:** [May 23, 2018, 10:10pm UTC](https://discourse.julialang.org/t/column-wise-broadcast-for-a-matrix/11113 "2018-05-23T22:10:08Z")
**Posts on this page:** 4
**Page:** 1
### Author:  [@pdeffebach](https://discourse.julialang.org/u/pdeffebach)
#### Post date: [May 23, 2018, 10:10pm UTC](https://discourse.julialang.org/t/column-wise-broadcast-for-a-matrix/11113/1 "2018-05-23T22:10:08Z")
Sorry if this has been posted a bunch but my googling has failed me. How do I broadcast a function by column for a 2 dimensional matrix? Say I want to, for each column in a matrix, normalize it with respect to the mean of that column. `normalize.(mymatrix)` will apply to each element, not each column.
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### Author:  [@NiclasMattsson](https://discourse.julialang.org/u/NiclasMattsson)
#### Post date: [May 23, 2018, 10:44pm UTC](https://discourse.julialang.org/t/column-wise-broadcast-for-a-matrix/11113/2 "2018-05-23T22:44:17Z")
I think the most elegant way to broadcast a function by column is to use `mapslices`. So try this:
```julia
mapslices(normalize, mymatrix, 1)
```
The third argument specifies the dimensions to broadcast over. So 1 for columns, 2 for rows, or a vector for high level multidimensional magic. See the [documentation](https://docs.julialang.org/en/stable/stdlib/arrays/#Base.mapslices) for more info.
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### Author:  [@pdeffebach](https://discourse.julialang.org/u/pdeffebach)
#### Post date: [May 23, 2018, 10:45pm UTC](https://discourse.julialang.org/t/column-wise-broadcast-for-a-matrix/11113/3 "2018-05-23T22:45:20Z")
Thank you! exactly what I was looking for.
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### Author:  [@rakeshvar](https://discourse.julialang.org/u/rakeshvar)
#### Post date: [May 24, 2018, 8:34pm UTC](https://discourse.julialang.org/t/column-wise-broadcast-for-a-matrix/11113/4 "2018-05-24T20:34:37Z")
For more complicated things, one can use the do syntax I guess.
```julia
mapslices(mymatrix, 1) do x
x/norm(x)
end
```