c#截取字符串归纳总结

var first = str.Substring(0, 1);

var last = str.Substring(str.Length - i,1); 

string left = "[";
string right = "]";
int IndexofLeft = stra.IndexOf(left);
int IndexofRight = stra.IndexOf(right);
string arr = stra.Substring(IndexofLeft + 1, IndexofRight - IndexofLeft -1);
string[] Array = arr.Split(string[]{‘,‘});
foreach(string a in Array)
{
  Console.WriteLine(a);
}

int qBefore = str.IndexOf("Q");
var before = str.Substring(0, qBefore- 1).Trim(); 

int qAfter = str.LastIndexOf("Q"); 
var after= str.Substring(qAfter + 1).Trim();