Introduction and examples of Swift-subscript scripting methods

Implement a custom string class that can be easily indexed to get a character value, or a portion of a string. It is also possible to assign values to a part by index.

Class substring{var str:string = "" Init (str:string) {self.str = str; }/** Subscript Script: Get/Set part string **/subscript (Start:int, length:int), string {get{Let Index 1 = Str.index (Str.startindex, offsetby:start) Let Index2 = Str.index (index1, offsetby:length) let        Range = Range (uncheckedbounds: (Lower:index1, Upper:index2)) return str.substring (With:range)}  set{Let tmp = str str = "" var s = "" var e = "" For (idx, item)                In tmp.characters.enumerated () {if (idx < start) {s + = "\ (item)"                } if (idx >= start + length) {e + = "\ (item)" }} str = s + newvalue + e}}/** Subscript script: Get/Set character **/subscript (index:int) string {get{return string (StR[str.index (Str.startindex, Offsetby:index)])} set{let tmp = str str = "" For (idx, item) in tmp.characters.enumerated () {if idx = = Index {str + = "\ (newvalue) "}else{str + =" \ (item) "}}}}} let str = Substri Ng (str: "baibai.com") print (str[7,3])//Get string: Comprint (Str[7])//Get character: c str[7,3] = "com"//Set part string str[0] = "H"//Set part character PR Int (str[0,10])/baibai.com

  You can also add an index function directly to the string class by extending the class

Extension string{subscript (start:int, length:int), String {get{let index1 = Self.index (Self.startindex, Offsetby:start) Let Index2 = Self.index (index1, offsetby:length) Let range = Ran            GE (uncheckedbounds: (Lower:index1, Upper:index2)) return self.substring (With:range)} set{ let tmp = self var s = "" var e = "" For (idx, item) in tmp.characters.enumerated                () {if (idx < start) {s + = "\ (item)} if (idx >= start + length) {e + = "\ (item)"}} s Elf = s + newvalue + e}} subscript (Index:int), string {get{return string (SE            Lf[self.index (Self.startindex, Offsetby:index)])} set{let tmp = self self = "" For (idx, item) In tmp.characters.enumerated () {if idx = = Index {self + = "\ (newvalue)"} else{self + = "\ (item)}}}}} var str =" baibai.com "Print (Str[7, 3]) print (str[7]) str[7,3] = "COM" str[0] = "H" Print (str[0,10])

A two-dimensional array is simulated to some extent using a one-dimensional array combined with subscript method

Class Matrix {Let    rows:int, Columns:int    var grid: [Double]         init (rows:int, columns:int) {        self.rows = Rows        self.columns = columns        Grid = Array (repeating:0.0, count:rows * columns)    }         func Indexisvalidforrow (Row:int, column:int), Bool {        return row >= 0 && row < rows && Column & gt;= 0 && Column < columns    }         subscript (Row:int, column:int), Double {        get {            assert (in Dexisvalidforrow (Row:row, Column:column), "Index Out of Range")            return grid[(Row * columns) + column]        }        S  ET {            assert (Indexisvalidforrow (Row:row, Column:column), "Index Out of Range")            grid[(Row * columns) + column] = NewValue        }}    } Let value = Matrix (rows:20,columns:20) value[10,10] = 20print (value[10,10])//20

Swift-Subscript Script methods Introduction and examples