slice

问题 I am getting the following errors from the code below: invalid indirect of typedSlice (type interface {}) cannot range over typedSlice (type interface {}) This is confusing to me because reflect.TypeOf(copy) matches the type of t . func Unmarshal(t reflect.Type) []interface{} { ret := []interface{}{} s := `[{"Name":"The quick..."}]` slice := reflect.Zero(reflect.SliceOf(t)) o := reflect.New(slice.Type()) o.Elem().Set(slice) typedSlice := o.Interface() json.Unmarshal([]byte(s), typedSlice) fmt

问题 How can I extract a specific field from each element of a Matlab struct array? >> clear x >> x(1).a = 6; >> x(2).a = 7; I'd like an array containing 6 and 7. Neither x(:).a nor x.a do what I want. >> x(:).a ans = 6 ans = 7 回答1: No problem - just use : arr = [x.a]; It will concat all of the values that you need. If you have a more complex data, you can use the curly bracers: b(1).x = 'John'; b(2).x = 'Doe'; arr = {b.x}; 回答2: For a multi-dimensional array, you need reshape([x.a], size(x)) 回答3:

问题 How can I extract a specific field from each element of a Matlab struct array? >> clear x >> x(1).a = 6; >> x(2).a = 7; I'd like an array containing 6 and 7. Neither x(:).a nor x.a do what I want. >> x(:).a ans = 6 ans = 7 回答1: No problem - just use : arr = [x.a]; It will concat all of the values that you need. If you have a more complex data, you can use the curly bracers: b(1).x = 'John'; b(2).x = 'Doe'; arr = {b.x}; 回答2: For a multi-dimensional array, you need reshape([x.a], size(x)) 回答3:

问题 Is it possible to initialize an slice with all 1's like in python? PYTHON: onesArray = np.ones(5) onesList = [1]*5 GOLANG onesSlice := make([]int, 5) for i:= 0; i < len(onesSlice); i++{ onesSlice[i] = 1 } Is it possible to do better than this? 回答1: Yes but you have to use a different syntax. oneSlice := []int{1, 1, 1, 1, 1} It's referred to as 'composite literal' Also, if there is reason to iterate (like calculating the values based loop variable or something) then you could use the range

问题 This question already has answers here : Why does go allow slicing from len(slice)? (3 answers) Closed 2 years ago . Here's the code to reproduce: package main import "fmt" func main() { var v []int v = append(v,1) v = append(v,v[1:]...) fmt.Println("hi", v) } v[1] will report index out of range , but v[1:]... won't, why? 回答1: That's how spec defines slice expressions For arrays or strings, the indices are in range if 0 <= low <= high <= len(a), otherwise they are out of range. For slices,

问题 This question already has answers here : Why does go allow slicing from len(slice)? (3 answers) Closed 2 years ago . Here's the code to reproduce: package main import "fmt" func main() { var v []int v = append(v,1) v = append(v,v[1:]...) fmt.Println("hi", v) } v[1] will report index out of range , but v[1:]... won't, why? 回答1: That's how spec defines slice expressions For arrays or strings, the indices are in range if 0 <= low <= high <= len(a), otherwise they are out of range. For slices,

问题 I want to remove all element from array except the element of array at 0th index ["a", "b", "c", "d", "e", "f"] Output should be a 回答1: You can set the length property of the array. var input = ['a','b','c','d','e','f']; input.length = 1; console.log(input); OR, Use splice(startIndex) method var input = ['a','b','c','d','e','f']; input.splice(1); console.log(input); OR use Array.slice method var input = ['a','b','c','d','e','f']; var output = input.slice(0, 1) // 0-startIndex, 1 - endIndex

问题 I want to remove all element from array except the element of array at 0th index ["a", "b", "c", "d", "e", "f"] Output should be a 回答1: You can set the length property of the array. var input = ['a','b','c','d','e','f']; input.length = 1; console.log(input); OR, Use splice(startIndex) method var input = ['a','b','c','d','e','f']; input.splice(1); console.log(input); OR use Array.slice method var input = ['a','b','c','d','e','f']; var output = input.slice(0, 1) // 0-startIndex, 1 - endIndex

问题 Example input: (type: string ) "[156, 100, 713]" Example conversion: (type: slice of int ) [156, 100, 713] 回答1: In addition to mhutter's answer, also note that your input string looks like a JSON array (maybe it is from a JSON text?). If you treat it like that, you may unmarshal its content into an []int slice. This won't be faster that directly parsing the numbers from it (as the encoding/json package uses reflection), but it is certainly simpler: s := "[156, 100, 713]" var is []int if err :

问题 I would like to slice a 2D NumPy array by an integer value, but I cannot find a way to do this properly. I need to slice the "border" of the matrix by a certain number of rows/columns. Say the array is: a = np.reshape(np.arange(25),(5,5)) print a [[ 0 1 2 3 4] [ 5 6 7 8 9] [10 11 12 13 14] [15 16 17 18 19] [20 21 22 23 24]] slice_val = 1 b = a[:-slice_val,:-slice_val] print "\n", b What I get is: [[ 0 1 2 3] [ 5 6 7 8] [10 11 12 13] [15 16 17 18]] , but I want something like this: [[6 7 8 ]