C#•3y ago

Idiomatic LINQ way to access both object and an object's property? [Answered]

var list = new List<string>();

foreach (Item item in items)
{
  foreach (string thing in item.Things)
  {
    list.Add($"{thing} + {item.OtherProperty}");
  }
}

return list;

var list = new List<string>();

foreach (Item item in items)
{
  foreach (string thing in item.Things)
  {
    list.Add($"{thing} + {item.OtherProperty}");
  }
}

return list;

I'd like to do this with LINQ. Normally I would use .Select(), but if the inner operation needs both an object (item) and an inner property (thing), I don't know of a clean way to do it. I can .Select() into a tuple containing both items, but this is really ugly. Any idea?

7 Replies

Tvde1•3y ago

IIRC SelectMany has a ResultSelector, can you access the parent there?

BecquerelOP•3y ago

i see - let me try that

Tvde1•3y ago

is this kind of what you want? https://sharplab.io/#v2:EYLgtghglgdgNAFxAJwK7wCYgNQB8ACATAAwCwAUEQIwX7EAE+VAdADKwCOA3BRQCoALWAHMA2gF16CITGEBnegF56MAKYB3CRQDeFevpUb6gkfW30AchDCqFytZsnmARBGdx6z4M/oBfDxaoYMCqyEr0VH5wegYOxjLCZpbWtuEOEknOAMbunhjO/pZBIWHKhH70FL485BQAbhBhkDAAnuHSInLMAMqqADaqWQgAshCtABQdskoAfFIJzFY2Xb0DQ+Mws/QAJM7aU8KLxaG+IGYwvs4AlFc1tFQAnONMxMwAUgD2sOMAojB1UGQHxgNhgCEWGnYag8zRaNzutUo5RMsh0MX0+AAzIwqMQMktUuZhKoEFx6HISWTfOjKuQDIxsbAEEVgqEksTSeTKX4qhQgA

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Tvde1•3y ago

in your case:

var list = items.SelectMany(item => item.Things.Select(thing => $"{thing} + {item.OtherProperty}"));

var list = items.SelectMany(item => item.Things.Select(thing => $"{thing} + {item.OtherProperty}"));

BecquerelOP•3y ago

that does look like pretty much it - awesome! thanks very much 😄

Tvde1•3y ago

You're welcome ^^

Accord•3y ago

✅ This post has been marked as answered!

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Idiomatic LINQ way to access both object and an object's property? [Answered]