How to remove decimals from file (round them)?-CodePudding

I have to open file, find all decimals, remove decimal part, round them and replace in the text. Result text should be print in the Console. I tried to do it, but the only thing I made was to remove the decimal part. Please tell me how to round them and replace in the result text. Here is my code:

Console.WriteLine("Enter path to first file:");
        String path1 = Console.ReadLine();
        
                    
        string text = File.ReadAllText(path1);
        string pattern = @"(\d )\.\d ";
        if(File.Exists(path1) ){
            
            foreach(string phrase in Regex.Split(text, pattern)){
                Console.Write(phrase);
            }
            
        Console.Write("Press any key to continue . . . ");
        Console.ReadKey(true);      
        }

CodePudding user response：

You can use @"\d ([\.\,]\d )" pattern to capture each number with any amount of decimals. Then use Regex.Replace with MatchEvaluator, where parse captured value as double then "cut" decimals by simple ToString("F0") (check about Fixed-point format).

Example below include decimals with comma , or . fraction separators with help of double.TryParse overload, where we can specify NumberStyles.Any and CultureInfo.InvariantCulture (from System.Globalization namespace) and simple replacement of comma , to dot .. Also works with negative numbers (e.g. -0.98765 in example):

var input = "I have 11.23$ and can spend 20,01 of it. " 
            "Melons cost 01.25$ per -0.98765 kg, " 
            "but my mom ordered me to buy 1234.56789 kg. " 
            "Please do something with that decimals.";
var result = Regex.Replace(input, @"\d ([\.\,]\d )", (match) =>
    double.TryParse(match.Value.Replace(",", "."), NumberStyles.Any, CultureInfo.InvariantCulture, out double value)
    ? value.ToString("F0")
    : match.Value);

// Result: 
// I have 11$ and can spend 20 of it.
// Melons cost 1$ per -1 kg,
// but my mom ordered me to buy 1235 kg.
// Please do something with that decimals.

On "Aaaa 50.05 bbbb 82.52 cccc 6.8888" would work too with result of "Aaaa 50 bbbb 83 cccc 7".

CodePudding user response：

You can use Math.Round on all matches that you can transform using Regex.Replace and a match evaluator as the replacement:

var text = "Aaaa 50.05 bbbb 82.52 cccc 6.8888";
var pattern = @"\d \.\d ";
var result = Regex.Replace(text, pattern, x => $"{Math.Round(Double.Parse(x.Value))}");
Console.WriteLine(result); // => Aaaa 50 bbbb 83 cccc 7

See the C# demo.

The \d \.\d regex is simple, it matches one or more digits, . and one or more digits. Double.Parse(x.Value) converts the found value to a Double, and then Math.Round rounds the number.