嗯,这可能是非常基本的问题(我觉得杀我)......但
什么是交错数组和多维数组之间的差异。 有一个在另一个的好处?
和为什么会在Visual Studio不允许我做了
MyClass的[] [] ABC =新MyClass的[10] [20];
(我们用来做,在C ++,但在C#它强调[20]用红色wriggly行..说无效排名符)
但高兴与
MyClass的[,] ABC =新MyClass的[10,20]。
最后,我怎么能初始化这一行(就像我们做简单的数组与 {新的XXX ...} {新的XXX ....}
)
MyClass的[] [] [,] itemscollection;
解决方案
一个交错数组是一个数组,数组的-,所以一个 INT [] []
是一个数组 INT []
,其中每一个可以是不同长度的,并占据其自己的块在存储器中。多维数组( INT [,]
)是一个单独的内存块(本质上是一个矩阵)。
您不能创建一个 MyClass的[10] [20]
,因为每个子阵列必须单独初始化,因为它们是独立的对象:
MyClass的[] [] ABC =新MyClass的[10] [];
的for(int i = 0; I< abc.Length;我++){
ABC [我] =新MyClass的[20]。
}
在 MyClass的[10,20]
是确定的,因为它正在初始化一个对象为10行和20列的矩阵
A MyClass的[] [] [,]
可initailized像这样(不编译尽管测试):
MyClass的[] [] [,] ABC =新MyClass的[10] [,] [,]
的for(int i = 0; I< abc.Length;我++){
ABC [我] =新MyClass的[20,30] [,]
为(诠释J = 0; J&其中; ABC [I] .GetLength(0); J ++){
为(中间体K = 0; K&其中; ABC [I] .GetLength(1); k ++){
ABC [I] [J,K] =新MyClass的[40,50]。
}
}
}
记住,CLR的是大量的一维数组访问进行了优化,所以采用交错数组可能会比同样大小的多维数组更快。
Well this may be very basic question (I feel like killing myself)... But
What is the difference between jagged array and Multidimensional array. Is there a benefit of one on another?
And why would the Visual Studio not allow me to do a
MyClass[][] abc = new MyClass[10][20];
(We used to do that in C++, but in C# it underlines [20] with red wriggly line.. Says invalid rank specifier)
but is happy with
MyClass[,] abc = new MyClass[10,20];
Finally how can I initialize this in a single line (like we do in simple array with {new xxx...}{new xxx....}
)
MyClass[][,][,] itemscollection;
解决方案
A jagged array is an array-of-arrays, so an int[][]
is an array of int[]
, each of which can be of different lengths and occupy their own block in memory. A multidimensional array (int[,]
) is a single block of memory (essentially a matrix).
You can't create a MyClass[10][20]
because each sub-array has to be initialized separately, as they are separate objects:
MyClass[][] abc = new MyClass[10][];
for (int i=0; i<abc.Length; i++) {
abc[i] = new MyClass[20];
}
a MyClass[10,20]
is ok because it is initializing a single object as a matrix with 10 rows and 20 columns
A MyClass[][,][,]
can be initailized like so (not compile tested though):
MyClass[][,][,] abc = new MyClass[10][,][,];
for (int i=0; i<abc.Length; i++) {
abc[i] = new MyClass[20,30][,];
for (int j=0; j<abc[i].GetLength(0); j++) {
for (int k=0; k<abc[i].GetLength(1); k++) {
abc[i][j,k] = new MyClass[40,50];
}
}
}
Bear in mind that the CLR is heavily optimized for single-dimension array access, so using a jagged array will likely be faster than a multidimensional array of the same size.