[Csharp] search location string str = "efef888wwww";-int I = str. indexOf ('W'); Console. writeLine (I); insert string strs = "esfewf"; string a = strs. insert (2, "111"); Console. writeLine (a); determines whether the specified string str = "rdgergr"; Console. writeLine (str. contains ("rd"); judge whether the specified string is at the end of string str = "f3g3g"; Console. writeLine (str. endsWith ("3g"); judge whether the specified string is in the starting position string str = "rgvrgvregv"; Console. writeLine (str. startsWith ("1rg"); replace the specified string str = "fwegfewgfv"; Console. writeLine (str. replace ('F', 'w'); converts a string to a char array string str = "huinuefnie"; char [] lines = str. toCharArray (); traverses the output foreach (char line in lines) {Console. writeLine (line);} specifies the index position, and the length is string str = "sdgergver"; string s = str. substring (3, 5); Console. writeLine (s );