[英]How to select data for particular date in linq using C#
我的清單包含以下格式的數據,
TF000040070004-29/08/12
TF000040070004-29/08/12
TF000040070005-29/08/12
TF000020010004-29/08/12
TF000020010007-29/08/12
TF000020010002-29/08/12
TF000010010012-29/08/12
TF000010010014-29/08/12
TF000010010014-29/08/12
TF000010010005-29/08/12
TF000010010005-29/08/12
TF000010010006-29/08/12
TF000010010002-29/08/12
TF000010010008-29/08/12
TF000010010008-29/08/12
TF000010010008-29/08/12
TF000010010008-29/08/12
我使用以下linq查詢來獲取計數,鍵值以及最小值和最大值。 現在,我要選擇特定日期的數據。
var serialNumbers = from sn in code
group sn by sn.Substring(0, 10) into g
select new { Key = g.Key,
Cnt = g.Count(),
Min = g.Min(v => v.Substring(10)),
Max = g.Max(v => v.Substring(10)) };
請嘗試以下操作:
from sn in rawData where sn.Substring(15, 8) == "29/08/12"
select sn;
然后,您可以將您的linq查詢( group by
等)附加到該...
如果您的字符串末尾沒有有效的DateTime,這將失敗。
var selectionDate = new DateTime(2012,8,29);
var serialNumbers = from sn in code
where DateTime.Parse(
sn.Trim().Substring(sn.Trim().Length-8,8),
new DateTimeFormatInfo {ShortDatePattern="dd/MM/yy"}) ==
selectionDate;
group sn by sn.Substring(0, 10) into g
select new { Key = g.Key,
Cnt = g.Count(),
Min = g.Min(v => v.Substring(10)),
Max = g.Max(v => v.Substring(10)) };
首先,您需要轉換數據以進行更好的操作。
var transformed = code.Select(item=>
{
var parts = item.Split(new string[]{"-"}, StringSplitOptions.None);
var keyPart = parts[0].Substring(2);
var key = long.Parse(keyPart);
var date = DateTime.Parse(parts[1]);
return new KeyValuePair<long, DateTime>(key, date);
}
轉換后,對強類型數據執行所需的查詢:
var date = DateTime.Today; // your date here
var result = transformed.Where(item => item.Value == date);
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