julia - 朱莉娅 | 数组元素作为另一个数组的参数

Question

当一个数组元素是另一个数组的参数时，我遇到了索引问题。它会导致“无效索引 1.0”错误。例如：

i = 0    

for l in 1:length
    for s in 1:ser
        for x in 1:s

        i = i + 1

        arr1[i] = x

        end
    end
end



for ts in 1:tiser

arr2[ts] = arr3[arr1[ts]]

end

这是您可以复制到 REPL 并查找错误的代码。我得到的是索引错误。

arr1 = Array{Float64,1}(1500)   
arr2 = Array{Float64,1}(10000)
arr3 = Array{Float64,1}(10000)


for z in 1:100

    arr3[z] = 1 + z

end


i = 0    

for l in 1:100
    for s in 1:5
        for x in 1:s

        i = i + 1

        arr1[i] = x

        end
    end
end



for ts in 1:10000

    arr2[ts] = arr3[arr1[ts]]

end

println(arr2[3])

谢谢

标签： julia

Answer 1

您需要转换浮点数arr1以将其用作索引。我修改了最小工作示例来工作：

arr1 = Array{Float64,1}(1500)   
arr2 = Array{Float64,1}(10000)
arr3 = Array{Float64,1}(10000)


for z in 1:100

    arr3[z] = 1 + z

end


i = 0    

for l in 1:100
    for s in 1:5
    for x in 1:s
        i = i + 1
        arr1[i] = x
    end
    end
end

println(arr1[1:20])

for ts in 1:10000
    from_arr1_as_index=Int(arr1[(ts-1)%1500+1])
    arr2[ts] = arr3[from_arr1_as_index]
end


println(arr2[3])