我有一个字符串列表,需要编写一个实现IComparer
接口的类来按照特定顺序排序。
目前我的实现如下:
public enum TimeBucket
{
[Description("0D")]
ZeroDay,
[Description("1D")]
OneDay,
[Description("1W")]
OneWeek,
[Description("2W")]
TwoWeek,
[Description("0M")]
ZeroMonth,
[Description("1M")]
OneMonth
}
public class TimeBucketComparer : IComparer
{
public static TimeBucketComparer Instance { get; } = new TimeBucketComparer();
private TimeBucketComparer()
{
}
public int Compare(object x, object y)
{
TimeBucket xvar = GetValue(string.Join("", x.ToString().Split(' ')));
TimeBucket yvar = GetValue(string.Join("", y.ToString().Split(' ')));
if (EqualityComparer<TimeBucket>.Default.Equals(xvar, default(TimeBucket)) &&
EqualityComparer<TimeBucket>.Default.Equals(yvar, default(TimeBucket)))
return String.CompareOrdinal(xvar.ToString(), yvar.ToString());
if (EqualityComparer<TimeBucket>.Default.Equals(xvar, default(TimeBucket))) return -1;
if (EqualityComparer<TimeBucket>.Default.Equals(yvar, default(TimeBucket))) return 1;
return xvar.CompareTo(yvar);
}
public TimeBucket GetValue(string description) => EnumExtensions.GetValueFromDescription<TimeBucket>(description);
}
public static class EnumExtensions
{
public static string GetDescription(this Enum value)
{
return ((DescriptionAttribute)Attribute.GetCustomAttribute(value.GetType().GetFields(BindingFlags.Public | BindingFlags.Static).Single(x => x.GetValue(null).Equals(value)),typeof(DescriptionAttribute)))?.Description ?? value.ToString();
}
public static T GetValueFromDescription<T>(string description)
{
var type = typeof(T);
if (!type.IsEnum) throw new InvalidOperationException();
foreach (var field in type.GetFields())
{
var attribute = Attribute.GetCustomAttribute(field,
typeof(DescriptionAttribute)) as DescriptionAttribute;
if (attribute != null)
{
if (attribute.Description == description)
return (T)field.GetValue(null);
}
else
{
if (field.Name == description)
return (T)field.GetValue(null);
}
}
throw new ArgumentException("Not found.", "description");
// or return default(T);
}
}
我的当前实现涉及到反射,因此需要很长时间。我之所以使用这种方式是因为需要通用实现。
输入至少有40000个Timebuckets记录需要排序。排序算法是Linq OrderBy,它是通用的,不能修改。因此,需要使用比较器。
我需要对字符串进行排序。是否有更好的方法不使用反射?
编辑:如果不清楚,我的输入是{"1M", "1D", "1W", "0D"},我需要的输出是{"0D", "1D", "1W", "1M"}
ZeroDay = 0, OneDay = 1, OneWeek = 7
等等。 - Zohar Peled