IGrouping does not contain a definition for Sum - linq

Question

Would anyone have an idea what's up here? I'm loading an XML file, parsing it and using LINQ to get some summary info. Here's the XML document:
<?xml version="1.0" encoding="utf-8"?>
<root>
<Ticker>
<Name>MSFT</Name>
<PurchaseDate>
2009-01-01
</PurchaseDate>
<Shares>44</Shares>
</Ticker>
<Ticker>
<Name>MSFT</Name>
<PurchaseDate>
2009-03-01
</PurchaseDate>
<Shares>33</Shares>
</Ticker>
<Ticker>
<Name>GOOG</Name>
<PurchaseDate>
2009-03-01
</PurchaseDate>
<Shares>122</Shares>
</Ticker>
<Ticker>
<Name>AAPL</Name>
<PurchaseDate>
2019-03-01
</PurchaseDate>
<Shares>89</Shares>
</Ticker>
</root>
My code:
var xmlStr = File.ReadAllText("ClientInfo.xml");
var Summary = XElement.Parse(xmlStr);
var data = from acct in Summary.Elements("Ticker")
select new
{
Ticker = (string)acct.Element("Name"),
Shares = (int)acct.Element("Shares")
};
var groupedDataByTicker = from acct in data
group acct by acct.Ticker into g
select new
{
Ticker = g.Key,
Shares = g.Sum(),
};
Works fine but when I add the g.Sum() bit I get this message:
'IGrouping>' does not contain a definition for 'Sum' and the best extension method overload 'Queryable.Sum(IQueryable)' requires a receiver of type 'IQueryable'
I can't make sense of it, what am I doing wrong?

Answer 1

In your code, you are trying to find the sum of the group itself.
Instead, you should be summing by the Shares property:
var groupedDataByTicker = from acct in data
group acct by acct.Ticker into g
select new
{
Ticker = g.Key,
Shares = g.Sum(row => row.Shares),
};