Standard deviation for float array JuliaLang

I'm trying to run std(list), where list is a Float array but I receive the next error:

"MethodError: objects of type Array{Float64,1} are not callable Use square brackets [] for indexing an Array."

And when using []:

"ArgumentError: invalid index: 0.4"

Which is the first value of my array.

I'm guessing "std()" is not valid while using float arguments, anyway to make it work??

(Right now I'm using juliabox 0.6.2)

1 Answer

This worked for me in JuliaBox 0.6.2:

VERSION
v"0.6.2"
A = [1 2 3 4 5]
1×5 Array{Int64,2}: 1 2 3 4 5
s = std(A)
1.5811388300841898

As pointed out by Hckr in the comments, you may have shadowed std something like this:

std = [1 2 3 4 5]
1×5 Array{Int64,2}: 1 2 3 4 5
std(std)
MethodError: objects of type Array{Int64,2} are not callable
Use square brackets [] for indexing an Array.

As pointed out by Bogumił Kamiński in the comments, in Julia 1.0.0 you need to do using Statistics to access the std function:

VERSION
v"1.0.0"
A = [1 2 3 4 5]
1×5 Array{Int64,2}: 1 2 3 4 5
# Error here because using Statistics is needed in 1.0.0.
std(A)
UndefVarError: std not defined
Stacktrace: [1] top-level scope at In[2]:1
using Statistics
std(A)
1.5811388300841898