I need replace variable in string from user. For example:
User input: Ssad asdsdqwdq jdiqwj diqw jd qwld j {price-40%} asd asd asd
I know how replace only {price} but I don't know how to replace other cases.
I need support these cases:
{price}
{price-xx%}
{price+xx%}
{price-xx}
{price+xx}
{price/xx}
{price*xx}
And user can use variable {price} many times.
After user submit text, my app replace variable {price} or calc {price-xx%} and create a new string.
If I understood your problem correctly then I think you can evaluate the whole expression without Replacing variables (might you have to change placements of variables)
First, add 'System.Data' name space in your project
then:
double price = 110;
double xx = 15;
double result = 0;
result = Convert.ToDouble(new DataTable().Compute($"({price-(price*xx)/100})", null));
Console.WriteLine("{price - xx%} = " + result);
result = Convert.ToDouble(new DataTable().Compute($"({price + (price * xx) / 100})", null));
Console.WriteLine("{price + xx%} = " + result);
result = Convert.ToDouble(new DataTable().Compute($"({price}-{xx})", null));
Console.WriteLine("{price - xx} = " + result);
result = Convert.ToDouble(new DataTable().Compute($"({price}+{xx})", null));
Console.WriteLine("{price + xx} = " + result);
result = Convert.ToDouble(new DataTable().Compute($"({price}/{xx})", null));
Console.WriteLine("{price / xx} = " + result);
result = Convert.ToDouble(new DataTable().Compute($"({price}*{xx})", null));
Console.WriteLine("{price * xx} = " + result);
https://github.com/davideicardi/DynamicExpresso/
static void Main(string[] args)
{
int price = 100;
Regex regex = new Regex(@"(?<=\{).*?(?=\})");
string userInput = "Hi. I want to buy your computer. I can't offer {price} USD, but I can offer {price-(price/100)*10} USD";
string text = userInput;
foreach (var item in regex.Matches(text))
{
string expression = item.ToString().Replace("price", price.ToString());
var interpreter = new Interpreter();
var result = interpreter.Eval(expression);
text = regex.Replace(text, result.ToString(),1);
text = ReplaceFirst(text, "{", string.Empty);
text = ReplaceFirst(text, "}", string.Empty);
}
Console.WriteLine("Result: " + text);
}
public static string ReplaceFirst(string text, string search, string replace)
{
int pos = text.IndexOf(search);
if (pos < 0)
{
return text;
}
return text.Substring(0, pos) + replace + text.Substring(pos + search.Length);
}
