c#代码工具箱-数字范围合并

 public class ScheduleWeekSpanModel
    {
        public int week_from { get; set; }

        public int week_to { get; set; }
    }

　　

//分割，例如 1;2;3;5;7;8;10;11;12;15
public static List<ScheduleWeekSpanModel> GetWeekSpans(string weeks)
        {
            var weekList = weeks.Split(';').ToList().Select(item => Int32.Parse(item)).OrderBy(i=>i).ToList();//转成数字并排序
            List<ScheduleWeekSpanModel> spans = new List<ScheduleWeekSpanModel>();
            var week_from = 0;//
            for (var i = 0; i <= weekList.Count; i++)
            {
                if (weekList.Count == 1)
                {
                    //只有一个元素
                    ScheduleWeekSpanModel obj = new ScheduleWeekSpanModel { week_from = weekList[i], week_to = weekList[i] };
                    spans.Add(obj);
                    break;
                }
                if (week_from == 0)
                {
                    week_from = weekList[i];

                }

                if (i + 1 == weekList.Count)
                {
                    //最后一个元素
                    ScheduleWeekSpanModel obj = new ScheduleWeekSpanModel { week_from = week_from, week_to = weekList[i] };
                    spans.Add(obj);
                    break;
                }

                if (weekList[i] == weekList[i + 1] - 1)
                {
                    continue;
                }
                else
                {
                    //不连续
                    ScheduleWeekSpanModel obj = new ScheduleWeekSpanModel { week_from = week_from, week_to = weekList[i] };
                    spans.Add(obj);
                    //重新开始
                    week_from = 0;
                }
            }

            return spans;
        }

　　

//例如 1;2;3;5;7;8;10;11;12;15显示为1-3;5;7-8;10-12;15
 public string DisplayWeeks(string weeks) 
{ 

                if (String.IsNullOrEmpty(weeks))
                    return string.Empty ;

                var weekSpans= GetWeekSpans(weeks);

                if (weekSpans == null || weekSpans.Count == 0)
                    return string.Empty;
//拼接输出
                StringBuilder sb = new StringBuilder();
                foreach(var weekspan in weekSpans)
                {
                    if (weekspan.week_from == weekspan.week_to)
                    {
                        sb.Append(weekspan.week_from);
                        sb.Append("; ");
                    }
                    else
                    {
                        sb.Append(weekspan.week_from);
                        sb.Append("—");
                        sb.Append(weekspan.week_to);
                        sb.Append("; ");
                    }
                }

                return sb.ToString();
            
        }