slice

I find that slice map function and channel are frequently mentioned together as reference types . However I notice that slices somethings exhibit none reference behavior like they can go stale: var s []int //must update slice value s = append(s, ...) or //must use pointer if we want to expose the change func foo(s *[]int) error //or change the function signature to return it like _append_ func foo(s []int) (r slice, err error) Usually I understand this by keeping the inner components of the slice discriptor implementation in mind: A slice value can be seen as a struct of len, cap and data

转载自： https://www.cnblogs.com/liuzhongchao/p/9159896.html 数组 数组是类型相同的元素的集合。例如，整数 5, 8, 9, 79, 76 的集合就构成了一个数组。Go不允许在数组中混合使用不同类型的元素（比如整数和字符串）。 声明 var variable_name [SIZE] variable_type 有很多声明数组的方式，让我们一个一个地介绍。 package main import ( "fmt" ) func main() { var a [3]int //int array with length 3 fmt.Println(a) } var a [3]int 声明了一个长度为 3 的整型数组。数组中的所有元素都被自动赋值为元素类型的 0 值。比如这里 a 是一个整型数组，因此 a 中的所有元素都被赋值为 0（即整型的 0 值）。 运行 上面的程序，输出为： [0 0 0] 。 数组的索引从 0 开始到 length - 1 结束。下面让我们给上面的数组赋一些值。 package main import ( "fmt" ) func main() { var a [3]int //int array with length 3 a[0] = 12 // array index starts at 0 a[1] =

I am trying to write my own matrix class in python, just for testing purposes. In reality, this matrix class is in c++ and I am using SWIG to interface between the two. However, for this question, it might be simpler to consider a pure python implementation of this matrix class. I want to be able to call this matrix class and use two-indexed slicing. For example, after we create 4x4 matrix of ones, >>> A = Matrix(4,4,1) I want to be able to get the sub 2x2 matrix: >>>> A[1:2,1:2] I've heard of the __getslice__ method, but this seems like it only allows single slicing, e.g. A[1:2] . So how can

I have a DICOM image loaded as a matrix in matlab. My question is, how do I show specific slices of that image in each orthogonal direction? Like view slice x at position 100, y=0, z=0 If your matrix is M, and has d dimensions (3, or what have you) and you want to plot a 1-D "slice" of one of the dimensions then: plot(squeeze(M(n1,n2, ...,:,...)); where n1,n2,... are the positions of dimension x,y,... where you want to slice, and the operator (:) is the dimension you want to plot. for example, given a 5 dimensional matrix M=rand(10,10,10,10,10), lets slice the 4-th dimension around some points

I have an issue with structs and maybe an issue with pointers, if my guess is correct. This struct has some fields and a field that holds a slice: type Bot struct { // ... connlist []Connection } This Connection looks like this: type Connection struct { conn net.Conn messages int32 channels []string joins int32 connactive bool } My problem is changing the value of connactive to true . Bot has a method that listens to the connection: func (bot *Bot) ListenToConnection(connection Connection) { reader := bufio.NewReader(connection.conn) tp := textproto.NewReader(reader) for { line, err := tp

string = "HELLO" print string[::-1] #as expected print string[0:6:-1] #empty string why ? I was amazed to see how easy it is to reverse a string in python but then I struck upon this and got lost. Can someone please explain why the second reverse does not works ? The reason the second string is empty is because you are telling the compiler to begin at 0, end at 6 and step -1 characters each time. Since the compiler will never get to a number bigger than six by repeatedly adding -1 to 0 (it goes 0, -1, -2, -3, ...) the compiler is programmed to return an empty string. Try string[6::-1] , this

How to get the reference to a slice of an array? var A = ['a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j']; A.mySlice = function(l, h){return this.slice(l,h)}; var B = A.mySlice(1,5); // ["b", "c", "d", "e"] It works for direct slices derived from A. But, how to get it for all slices derived? (in this case for B) B.mySlice = function(l, h){return this.slice(l,h)}; A[3] = 33; A.mySlice(1,5) // ["b", "c", 33, "e"] => ok B.mySlice(0,3) // ["b", "c", "d"] => I would want ["b", "c", 33] I don't think you can do this with native JS arrays (well, not in a straightforward manner anyway). I think the