C# String.Format() to remove decimals after hundredths and remove decimals completely if decimals are trailing zeros

Question

These floats

77.1455
52.00
714.1554
5552.0001

Should become like these

77.14
52
714.15
5552

Some suggested

String.Format("G");
String.Format("G29");
String.Format("0.00");

But they don't work as I need.

Answer 1

Use the "####.##" pattern to achieve the desired result with natural rounding (see bottom example for truncation). Few examples:

var f1 = 1000.3455f;
var result = f1.ToString("####.##");
//result = 1000.35

Round's down eliminating trailing zeros:

f1 = 1000.0001f;
result = f1.ToString("####.##");
//result = 1000;

Add a comma if to the formatting string for comma separated numbers >= 1000:

var f1 = 1000.3455f;
f1.ToString("#,###.##");
//result = 1,000.35;

And if you want to remove the trailing numbers beyond hundredths without natural rounding:

var f1 = 1000.3455f;
f1 = (float)Math.Round(f1, 2, MidpointRounding.ToZero);
result = f1.ToString("#,###.##");
//result = 1,000.34

Answer 2

You can truncate the value after two decimal places:

(Math.Truncate(100 * value) / 100).ToString();

Full sample:

static void Main(string[] args)
{
    float[] values = { 77.1455f, 52.00f, 714.1554f, 5552.0001f };
    string[] formattedValues = Format(values);
    Console.WriteLine(string.Join(Environment.NewLine, formattedValues));
}  

private static string[] Format(float[] values)
{
    return Array.ConvertAll(values, Convert);
}

private static string Convert(float value)
{
    return (Math.Truncate(100 * value) / 100).ToString();
}