Get max

  • Thread starter Thread starter shapper
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S

shapper

Hello,

I am trying to get the maximum Id value from all Asset nodes in a XML
file:
private XDocument _assets;
// ...
Int32 id = _assets.Root.Elements("Asset").Max(s => Int32.Parse
(s.Element("Id").Value));

I am not sure if this is the best way to do it.
And how can I define a default value 1 if there are no nodes Asset in
the file?

Thanks,
Miguel
 
And how can I define a default value 1 if there are no nodes Asset in
the file?
Click to expand...

First, set up an XQuery test for Asset nodes. if none, set the id to 1.
If there are some, then run your max query. Without spending time
playing, I am not sure if that is the most "efficient" query you can
have.

Peace and Grace,

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shapper said:
Hello,

I am trying to get the maximum Id value from all Asset nodes in a XML
file:
private XDocument _assets;
// ...
Int32 id = _assets.Root.Elements("Asset").Max(s => Int32.Parse
(s.Element("Id").Value));

I am not sure if this is the best way to do it.
And how can I define a default value 1 if there are no nodes Asset in
the file?

Thanks,
Miguel
Click to expand...

That's pretty efficient. Unless you have some extra information, like
that the elements are sorted by id, then there is no method that is much
better as you have to loop though all the nodes to get the max value.

The Max method throws an exception if there are no items, so you can use
the Aggregate method instead to get a default value:

int? max =
_assets
.Root
.Elements("Asset")
.Select(s => Int32.Parse(s.Element("Id").Value))
.Aggregate(
(int?)null,
(a, i) => !a.HasValue || a.Value < i ? i : a
);
 
That's pretty efficient. Unless you have some extra information, like
that the elements are sorted by id, then there is no method that is much
better as you have to loop though all the nodes to get the max value.

The Max method throws an exception if there are no items, so you can use
the Aggregate method instead to get a default value:

   int? max =
     _assets
     .Root
     .Elements("Asset")
     .Select(s => Int32.Parse(s.Element("Id").Value))
     .Aggregate(
       (int?)null,
       (a, i) => !a.HasValue || a.Value < i ? i : a
      );
Click to expand...

Thank you Goran and Gregory.
 
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