Updating One List with values from another list based on a condition

Question

I have two lists lets say:

List1 = [{"name":"john", "limit":"21"},{"name":"edith", "limit":"21"}, {"name":"sam", "limit":"50"}]

List2 = [{"name":"john", "limit":"21"},{"name":"john", "limit":"21"} {"name":"edith", "limit":"21"}, {"name":"sam", "limit":"30"}, {"name":"sam", "limit":"30"}]

What is the best way to update elements in List2 with values from elements in List1 based on the condition that the value of name in List1 is equal to value of name in List2

I'm hoping I can find a solution using LINQ, like one below used to select elements

var list = List2.FindAll(y => List1.Any(x => y.name==x.name));

Answer 1

Since your condition is a simple "equals" condition, you can use a join

from source in list1
join target in list2 on source.name equals target.name
select new {target.name, source.limit}

Here's a simple test based on the data from the question:

var list1 = new List<dynamic>{new {name = "john", limit = "21"}, new {name = "edith", limit = "21"}, new {name = "sam", limit = "50"}};
var list2 = new List<dynamic>{new {name = "john", limit = "21"}, new {name = "john", limit = "21"}, new {name = "edith", limit = "21"}, new {name = "sam", limit = "30"}, new {name = "sam", limit = "30"}};

var query = from source in list1
    join target in list2 on source.name equals target.name
    select new {target.name, source.limit};

foreach (var x in query)
{
    Console.WriteLine($"name = {x.name}, limit = {x.limit}");
}

Outputs:

name = john, limit = 21
name = john, limit = 21
name = edith, limit = 21
name = sam, limit = 50
name = sam, limit = 50