使用Julia使用in()和元组数组时出错 [英] Error using in() with an array of tuples using Julia

问题描述

我有2个元组数组，并且有一个循环询问一个元素是否在另一个元素中. 在每一步中，我都会询问coord数组中包含的元组是否在Y数组中.除了一个我无法解释原因的元素之外，该循环工作正常.这就是我所拥有的:

I have 2 arrays of tuples and I have a loop asking if one element is in the other. At each step I ask if the tuple contained in the coord array is in the Y array. The loop works fine except for one element which I cant explain why. Here is what I have :

Y[55:65] # This is the array I want to check at each step if my state is in or not.

11个元素的数组{Any，1}:(2.0，1.0)(3.0，1.0)(4.0，1.0)(5.0， 1.0)(6.0，1.0)(7.0，1.0)(8.0，1.0)(9.0，1.0)(10.0，1.0)(11.0，1.0)(12.0，1.0)

11-element Array{Any,1}: (2.0, 1.0) (3.0, 1.0) (4.0, 1.0) (5.0, 1.0) (6.0, 1.0) (7.0, 1.0) (8.0, 1.0) (9.0, 1.0) (10.0, 1.0) (11.0, 1.0) (12.0, 1.0)

coord[i-1]  # this is one element of coord that is in Y

0维数组{元组{Float64，Float64}，0} :( 6.0，1.0)

0-dimensional Array{Tuple{Float64,Float64},0}: (6.0, 1.0)

coord[i] # this is an other element of coord that is in Y

0维数组{元组{Float64，Float64}，0} :( 7.0，1.0)

0-dimensional Array{Tuple{Float64,Float64},0}: (7.0, 1.0)

但是当我测试它们在Y位置时:

But then when I test when they are in Y:

in(coord[i],Y[55:65]) # testing if coord[i] is in Y

false

false

in(coord[i-1],Y[55:65]) # testing if coord[i-1] is in Y

true

true

我不明白:它们在Y中以相同的方式表示，它们具有相同的类型，为什么我要使用in()来获得一个在其中而不是另一个?

I dont understand: they are both represented in the same way in Y, they have the same type, why do I get from using in() that one is in and not the other?

我使用的是Julia版本0.6.3.

I use Julia version 0.6.3.

提前感谢您的帮助！

推荐答案

您是怎么得到coord和Y的?如果通过计算而不是直接分配获得它们，则即使它们显示正确，它们也可能不完全相同.例如:

How did you get coord and Y? If you get them by calculations rather than direct assignments, they may not be exactly equal even if they are displayed so. For example:

julia> p1 = fill((6.0, 1.0))
0-dimensional Array{Tuple{Float64,Float64},0}:
(6.0, 1.0)

julia> p2 = fill((7.0 + 3eps(), 1.0))
0-dimensional Array{Tuple{Float64,Float64},0}:
(7.000000000000001, 1.0)

julia> Y = [p1, p2]
2-element Array{Array{Tuple{Float64,Float64},0},1}:
 (6.0, 1.0)
 (7.0, 1.0) # NOTE that it get truncated in display but the content did not changed!

julia> x = fill((6.0, 1.0))
0-dimensional Array{Tuple{Float64,Float64},0}:
(6.0, 1.0)

julia> x in Y
true

julia> x = fill((7.0, 1.0))
0-dimensional Array{Tuple{Float64,Float64},0}:
(7.0, 1.0)

julia> x in Y
false

在这种情况下，您可以在比较之前对它们进行四舍五入，或者使用isapprox(或≈运算符，在\approx + Tab中在Julia中键入)手动编写in函数

If this is the case, you can either round them before comparing or write the in function mannually using isapprox (or the ≈ operator, typed in Julia by \approx + Tab)

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