can anyone help me to understand when to use where vs Select in LINQ… my understanding for where COndition is when you are applying filters we should use WHERE but want to confirm on the same.
->Use where when you want to filter elements based on certain criteria.
->Use select when you want to project elements into a new form or extract specific properties from them.
Regards
Where -
→ The Where function is used to filter elements from a collection based on a specified condition.
→ It returns a new collection containing only the elements that satisfy the specified condition.
Select -
→ The Select function is used to transform elements of a collection into a new form.
→ It returns a new collection containing the transformed elements.
Hope it helps!!
e.g. this is your table
if you read this excel as datatable variable e…g dt
you can use select like this
dt.asEnumerable.Select(function(x) x.field(of string)("JSON Field"))ToList
this will return a the JSON Field column as a list variable…
you can use where to do the following
dt.asEnumerable.where(function(x) x.field(of string)("JSON Field") = "first_name").CopyToDatatable
this will return the datatable but filtered by JSON Field = first_name
you can combine where and select like this
dt.asEnumerable.where(function(x) x.field(of string)("JSON Field") = "first_name").CopyToDatatable.asEnumerable.Select(function(x) x.field(of string)("JSON Field"))ToList
this will return column json field as a list but will be filtered by jsonfield = first_name
@devasaiprasad_K
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Hi ,
where : This clause is used for filtering elements based on a specified condition. It’s similar to the WHERE clause in SQL. When you want to select elements that satisfy certain criteria, you use where .
select : This clause is used for projecting data into a new form. It’s similar to the SELECT clause in SQL. When you want to transform the elements in some way (like selecting specific properties, performing calculations, or projecting them into a different data structure), you use select .
(From num In numbers
Where num Mod 2 = 0
Select num * 2).ToList()
Whereis used to filter elements based on a condition (num Mod 2 = 0filters even numbers in this case).Selectis used to transform each element (double the even numbers in this case).ToList()converts the resulting sequence into a list.
If the numbers collection contains the elements 1, 2, 3, 4, 5, 6, 7, 8, 9, and 10,
- The
Whereclause filters out only the even numbers, which are 2, 4, 6, 8, and 10. - The
Selectclause doubles each even number, resulting in 4, 8, 12, 16, and 20. - Finally,
ToList()converts the sequence 4, 8, 12, 16, and 20 into a list.
Together, this LINQ query filters even numbers from the numbers collection and doubles them, resulting in a list of even numbers doubled.
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@PVSneha_Nair - Thanks for the clear explanation…loved it
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@jack.chan @PVSneha_Nair - Thanks for the clear explanation…loved it
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have a look also here:
[HowTo] LINQ (VB.Net) Learning Catalogue - Help / Something Else - UiPath Community Forum
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