[英]How to convert Array{Float64, 1} to float in julia?
Someone knows how to convert an array{Float64,1} to a Float64? 有人知道如何将数组{Float64,1}转换为Float64吗?
When I do: 当我做:
M=rand(5,5)
a=M[:,1]' * M[:,1]
if a<0
print("Less than 0")
else
print("more")
end
I have an error: " isless has no method matching isless(::Array{Float64,2}, ::Int 32) in < at operators.jl:32 我有一个错误:“isless在<at operators.jl:32中没有匹配isless(:: Array {Float64,2},:: Int 32)的方法
Can anyone tell me please how to convert the array{Float64,1}
a to a float64
or tell me how to compare a 1 element array a to a float? 有谁能告诉我如何将
array{Float64,1}
转换为float64
或告诉我如何将1元素数组a与浮点数进行比较?
Thank you 谢谢
This operation really only makes sense when you are certain that your Array{Float64, 1}
has a single element. 当您确定
Array{Float64, 1}
具有单个元素时,此操作才有意义。 In this case you can access it as a[1]
. 在这种情况下,您可以将其作为
a[1]
访问。
For your example I'd recommend using the dot
function ( a = dot(M[:,1], M[:, 1])
) or the norm
function ( a = norm(M[:, 1])^2
) 对于你的例子,我建议使用
dot
函数( a = dot(M[:,1], M[:, 1])
)或norm
函数( a = norm(M[:, 1])^2
)
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