How to make a vlookup using LINQ

[ppr (Peter Preuss)]

@Shanitah_Isa

im working on big data

Can you confirm this requirement?

if so have a look here:

LINQ query running for long hours

Let us introduce the next changes [grafik] we are creating lists with the concatenated strings from dtold, dtnew and creating a dictionary of only the items common in both lists dtNewSet.asEnumerable.Select(Function (x) String.Join(“#”, arrColSet.Select(Function (k) x(k).toString.ToLower.Trim))).Distinct().toList dtOldSet.asEnumerable.Select(Function (x) String.Join(“#”, arrColSet.Select(Function (k) x(k).toString.ToLower.Trim))).Distinct().toList ListDT1.Intersect(ListDT2).ToDictionary(Fun…

And
[HowTo] Overview on different options for grouping data and processing the groups - News / Tutorials - UiPath Community Forum

whenever an update is to be done on a subset, then filter before update or atleast keep the processing cost as low as possible.

• when running a statement twice, also it is comsuming processing effort twice

When using the Count > 0 it has no chance to stop when the first was found and checks all. We should rewrite to an Any()

CA1827: Do not use Count/LongCount when Any can be used (code analysis) - .NET

Als we have a chance to rewrite it to a FirstOrDefault and will execute it only 1 time