osukey/osu.Game/Utils/FormatUtils.cs

namespace osu.Game.Utils
{
	public static class FormatUtils
	{
		/// <summary>
        /// Turns the provided accuracy into a percentage with 2 decimal places.
		/// Omits all decimal places when <paramref name="accuracy"/> equals 1d.
        /// </summary>
        /// <param name="accuracy">The accuracy to be formatted</param>
        /// <returns>formatted accuracy in percentage</returns>
		public static string FormatAccuracy(this double accuracy) => accuracy == 1 ? "100%" : $"{accuracy:0.00%}";

		/// <summary>
        /// Turns the provided accuracy into a percentage with 2 decimal places.
		/// Omits all decimal places when <paramref name="accuracy"/> equals 100m.
        /// </summary>
        /// <param name="accuracy">The accuracy to be formatted</param>
        /// <returns>formatted accuracy in percentage</returns>
		public static string FormatAccuracy(this decimal accuracy) => accuracy == 100 ? "100%" : $"{accuracy:0.00}%";
	}
}