LINQ 101 question

[Mike P]

In this LINQ example, how do you get at the values within the groupings?

string[] anagrams = {"from", "salt", "earn ", "last ", "near ", "form
"};

var orderGroups = anagrams.GroupBy(
w =w.Trim(),
new AnagramEqualityComparer());
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[Jon Skeet [C# MVP]]

On Aug 20, 4:46*pm, Mike P <[e-mail]:

In this LINQ example, how do you get at the values within the groupings?

string[] anagrams = {"from", "salt", "earn ", "last ", "near ", "form
"};

* * * * var orderGroups = anagrams.GroupBy(
* * * * * * * * * * w =w.Trim(),
* * * * * * * * * * new AnagramEqualityComparer());

GroupBy returns an IGrouping (IIRC) which has a Key property and
implements IEnumerable<Tfor the appropriate T - so you typically
just use "foreach" over it.

Here's an example:
using System;
using System.Collections.Generic;
using System.Linq;

class Test
{
static void Main()
{
string[] strings = { "These", "strings", "will",
"be", "grouped", "by", "length", "and", "then",
"displayed", "in", "their", "groups" };

var groups = strings.GroupBy(x =x.Length);

foreach (var group in groups)
{
Console.WriteLine("Words of length: {0}", group.Key);
foreach (var word in group)
{
Console.WriteLine(" {0}", word);
}
}
}
}

Jon

[vbMark]

"Jon Skeet [C# MVP]" <sk***@pobox.comwrote in news:05bf5f2b-589f-44db-
be***************@m45g2000hsb.googlegroups.com:

On Aug 20, 4:46*pm, Mike P <[e-mail]:

>In this LINQ example, how do you get at the values within the

groupings?

>>
string[] anagrams = {"from", "salt", "earn ", "last ", "near ", "form
"};

* * * * var orderGroups = anagrams.GroupBy(
* * * * * * * * * * w =w.Trim(),
* * * * * * * * * * new AnagramEqualityComparer());

GroupBy returns an IGrouping (IIRC) which has a Key property and
implements IEnumerable<Tfor the appropriate T - so you typically
just use "foreach" over it.

Here's an example:
using System;
using System.Collections.Generic;
using System.Linq;

class Test
{
static void Main()
{
string[] strings = { "These", "strings", "will",
"be", "grouped", "by", "length", "and", "then",
"displayed", "in", "their", "groups" };

var groups = strings.GroupBy(x =x.Length);

foreach (var group in groups)
{
Console.WriteLine("Words of length: {0}", group.Key);
foreach (var word in group)
{
Console.WriteLine(" {0}", word);
}
}
}
}

Jon

What if I only want the first item and do not want to do a foreach?

I want to do something like this:

string myString = strings[0];

But that is not an option.

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[Peter Duniho]

On Thu, 21 Aug 2008 12:45:38 -0700, vbMark <[e-mail]:

What if I only want the first item and do not want to do a foreach?

I want to do something like this:

string myString = strings[0];

But that is not an option.

Try the System.Linq.Enumerable.First() method. For example, if you want
the group of the shortest words:

Console.WriteLine("The shortest words have {0} characters. They
are:", groups.First().Key);
foreach (var word in groups.First())
{
Console.WriteLine(" {0}", word);
}

Pre-LINQ, you could of course always just put a "break" at the bottom of
your "foreach()" loop to ensure that you only ever process the first
element. But LINQ makes it nicer. :)

Pete