ORing LINQ Query in linq to object, built using expression trees

Question

I want same field combine with ORs and between two diffferent fileds with AND.

ex - If they have the same Field value, those all ORed. This allows us to say "State", "eq", "CA", OR "State", "eq", "TX" AND "FirstName", "eq", "John".

(State==CA || State==TX) AND FirstName==John)

people.Where(p => p.State == "CA" || p.State = "TX").Where(p => p.FirstName == "John") — Milos Mijatovic, May 03 '15 at 05:32
Why are you building the query using expressions if it's a linq to objects query? — Servy, May 04 '15 at 15:56

score 0 · Answer 1 · edited Jun 20 '20 at 09:12

There are a couple of ways you can do this:

1. Chain `Where()s`

You can chain together two Where() statements, the first one with the OR and the second satisfying the AND. This can get to be really useful when you have a query that you're programmatically/dynamically building:

var output = input
                .Where(a => a.State == "CA" || a.State == "TX")
                .Where(a => a.FirstName == "John");

Since the Where() filters are run in series, the effect is a logical AND of the conditions in each.

2. Parenthetical Logic

You can also just use parentheses to dictate the order of operation:

var output = input
                .Where(a => (a.State == "CA" || a.State == "TX") 
                             && a.FirstName == "John");

ORing LINQ Query in linq to object, built using expression trees

1 Answers1

1. Chain Where()s

2. Parenthetical Logic

1. Chain `Where()s`