注意:使用LINQ join解决了这个问题。
我需要比较源列表中的列表值,如果它存在于目标列表中,如果是,则将其保存到第三个列表中。
我写的代码确实可以工作,但它花费了很多时间,因为我的Source List有30k个项目,并且它将每个项目的值与1500万的目标列表进行比较,这需要很多时间。因为它每次都会遍历整个列表(30k *1500万次)
请看代码,它显然不是最优的,但可以完成工作。
// The below code will generate the lists from CSV file
The lists are below for sample
**Source List**
FileId FilePath FileChecksum
1 somepath A check1
2 somepath AA check2
3 somepath AAB check3
4 somepath B check4
5 somepath BB check5
**Destination List**
StepId StatusID JobId ProjectId FileId FilePath
5 6 4 2091 577206853 somepath A
5 6 4 2092 577206853 somepath AA
5 6 4 2093 577206853 somepath AAA
5 6 4 2094 577206853 somepath AB
5 6 4 2095 577206853 somepath A
5 6 4 2096 577206853 somepath B
5 6 4 2097 577206853 somepath BB
List<Source> SourceList = File.ReadAllLines(@"D:\source.csv").Skip(1).Select(v => Source.SourceFromCSv(v)).ToList();
List<Destination> DestinationList = File.ReadAllLines(@"D:\Destination.csv").Skip(1).Select(d => Destination.FromDestinationCSV(d)).ToList();
//This will compare and create a new list
var result1 =
from s in SourceList
from d in DestinationList
where (d.FilePath.ToLower() == s.FilePath.ToLower())
select (d.StepId + "," + d.StatusId + "," + d.JobId + "," +
d.ProjectId + "," + d.FileId + "," + d.FilePath + "," +
s.FileChecksum);
Expected Result:
StepId StatusID JobId ProjectId FileId FilePath FileChecksum
5 6 4 2091 577206853 somepath A check1
5 6 4 2092 577206853 somepath AA check2
5 6 4 2095 577206853 somepath A check1
5 6 4 2096 577206853 somepath B check4
5 6 4 2097 577206853 somepath BB check5
https://stackoverflow.com/questions/56716705
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