Last index

Going back to the way you originally posed this question, you might find it easier to get the indices of all the operators 'in one go' using a regular expression:

using System;

using System.Text.RegularExpressions;

class Program

{

static void Main()

{

string expression = "4+2.345/3";

string regex = @"(\+|-|\*|/)"; // need to escape + and * as regex metacharacters

MatchCollection ops = Regex.Matches(expression, regex);

foreach(Match op in ops)

{

Console.WriteLine("{0} : {1}", op.Index, op.Value);

}

Console.ReadKey();

}

To use LastIndexOf you'd need to use this overload (http://msdn.microsoft.com/en-us/library/1tw91fa3.aspx) which starts the search at a specified position.

1 Reply

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Vulpes15y ago
Going back to the way you originally posed this question, you might find it easier to get the indices of all the operators 'in one go' using a regular expression:

using System;
using System.Text.RegularExpressions;

class Program
{
static void Main()
{
string expression = "4+2.345/3";
string regex = @"(\+|-|\*|/)"; // need to escape + and * as regex metacharacters
MatchCollection ops = Regex.Matches(expression, regex);
foreach(Match op in ops)
{
Console.WriteLine("{0} : {1}", op.Index, op.Value);
}
Console.ReadKey();
}
}

To use LastIndexOf you'd need to use this overload (http://msdn.microsoft.com/en-us/library/1tw91fa3.aspx) which starts the search at a specified position.