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mean

mean(v[, region])

Compute the mean of whole array v, or optionally along the dimensions in region. Note: Julia does not ignore NaN values in the computation. For applications requiring the handling of missing data, the DataArray package is recommended.

Examples

julia> xsum = rand(5)
       mean(xsum)
0.38190307541901564

julia> A = rand(3)
3-element Array{Float64,1}:
 0.443922
 0.79404 
 0.959896
julia> mean(A)
0.6369315513562785

1. Compute the mean of a 1-dimensional array:

   julia> v = [1, 2, 3, 4, 5];
   julia> mean(v)
   3.0

   This example calculates the mean of the array v, which is 3.0.

2. Compute the mean along a specific dimension of a multi-dimensional array:

   julia> A = [1 2 3; 4 5 6; 7 8 9];
   julia> mean(A, dims = 1)
   1×3 Array{Float64,2}:
   4.0  5.0  6.0

   Here, the mean function is used to calculate the mean along the first dimension (columns) of the 2-dimensional array A. The result is a 1x3 array with the means of each column.

3. Compute the mean along multiple dimensions:

   julia> B = [1 2 3; 4 5 6; 7 8 9; 10 11 12];
   julia> mean(B, dims = (1, 2))
   1-element Array{Float64,1}:
   6.5

   In this example, the mean function calculates the mean along both dimensions of the 2-dimensional array B. The result is a 1-element array with the overall mean of the array.

Common mistake example:

julia> v = []
julia> mean(v)
ERROR: MethodError: no method matching mean(::Array{Any,1})

Here, an empty array v is provided to the mean function, which results in a MethodError because Julia cannot determine the appropriate method to use. Make sure to provide a non-empty array to calculate the mean accurately.

See Also

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