Mean Row of Matrix

3
votes

I'm trying to use mean(A,1) to get the mean row of a matrix A, but am getting an error.

For example, try running the command mean(eye(3), 1).
This gives the error no method mean(Array{Float64,2},Int32).

The only documentation I can find for the mean function is here:
http://docs.julialang.org/en/release-0.1/stdlib/base/#statistics

mean(v[, region])

Compute the mean of whole array v, or optionally along the dimensions in region.

What is the region parameter?

EDIT: for Julia 0.7 and higher, write this as mean(v, dims=1).

2
julia
It must be something with your installation, mean(eye(3),1) works just fine here. - juliohm
@juliohm I have since discovered that it was something wrong with JuliaStudio (a Julia IDE) in particular. The statement works fine when run directly through julia.bat. - Timothy Shields
I'll make my comment into an answer so that you can close the question. - juliohm

2 Answers

5
votes
julia> using Statistics
julia> A = [[1 2 3];[ 4 5 6]]
2×3 Array{Int64,2}:
 1  2  3
 4  5  6

# Column means
julia> mean(A, dims=1)
1×3 Array{Float64,2}:
 2.5  3.5  4.5

# Row means
julia> mean(A, dims=2)
2×1 Array{Float64,2}:
 2.0
 5.0
0
votes

It must be something with your installation, mean(eye(3),1) works just fine here.