I don't understand why the following case doesn't match. Null should be an instance of Any, but it doesn't match. Can someone explain what is going on?
val x = (2, null)
x match {
case (i:Int, v:Any) => println("got tuple %s: %s".format(i, v))
case _ => println("catch all")
}
prints catch all
Thanks.
...
I have a linq to sql statement which returns a set of Customer details to a customer object
var customers = from .....
I then use
if(customers.Count() > 0)
{
return customers.First();
}
else
{
return null;
}
but customers.Count()
throws a
'customers.Count()' threw an exception of type 'System.NotSupportedException' int ...
Like... is it 0 like in C++? Or is it some "special" object? Or maybe something totally different?
-- EDIT --
I do know what it is, the question is rather - how it's done
...
Product Version: NetBeans IDE 6.8 (Build 200912041610)
Java: 1.6.0_17; Java HotSpot(TM) Client VM 14.3-b01
System: Windows 7 version 6.1 running on x86; Cp1252; en_GB (nb)
Hello, newbee java programmer here and wondering if someone can help, I have been having some problems updating a GUI for a desktop application in netbeans, here are ...
Hi all,
I have a, I think fairly easy, question, but I can't figure out what I'm doing wrong. I have a function which i call with PHP's function eval. I'm expecting an, selfbuilt, ArrayList to get as a result. But instead when I use gettype I see the result is NULL. Even though I'm using return in the eval-ed function.
As far as I'm a...
this is my code -
Dim provider As CultureInfo = CultureInfo.InvariantCulture
Dim a1 As DateTime = Nothing
insexp = DateTime.ParseExact(date1.SelectedValue, "MMMM yyyy", provider)
If a1.Month = Today.Month AndAlso a1.Year = Today.Year Then
a1 = Today.Date
End If
...
I am trying to get a count of each value in a table using the following SQL:
SELECT col, COUNT(col)
FROM table
GROUP BY col
(There's a WHERE clause in the real code, but it has no impact).
When I run this I get results like so:
a - 5
b - 4
<null> - 0
It doesn't matter how many null entries I have, it always shows a coun...
NSArray *array = [[NSArray alloc] initWithObjects:@"ΕΛΤΑ",
@"ΕΛΤΑ COURIER", @"ACS", @"ACS ΕΞΩΤΕΡΙΚΟ",
@"DHL", @"INTERATTICA", @"SPEEDEX",
@"UPS", @"ΓΕΝΙΚΗ ΤΑΧΥΔΡΟΜΙΚΗ", @"ΜΕΤΑΦΟΡΙΚΕΣ ΕΞΩΤΕΡΙΚΟΥ", nil];
This is working because it has nil at the end.
But I add objects l...
I have the following line of code
if (DBNull.Value.Equals(o) || o != null)
where o is object o in row.ItemArray I keep getting an error of -->
Xml type "List of xdt:untypedAtomic" does not support a conversion from Clr type "DBNull" to Clr type "String".
What I don't understand is that when I step through my code this if should be...
I've written a simple chat program to experiment with some basic tcp/socket concepts. For some reason I've found that when I close my writer stream (which I am getting from the TcpClient.GetStream() function) it will send one final null message to my server. To top it all off it doesn't do this if I send one final message over the stream...
I am having difficulty setting an empty TextBox to null on an nullable DB Field.
XAML
<y:TextBox Text="{Binding Year1Cost, Mode=TwoWay,
UpdateSourceTrigger=PropertyChanged,
NotifyOnValidationError=True,
ValidatesOnDataErrors=True,
ValidatesOnExceptions=True,
StringFormat=\{0:c\}}" Grid.Row="3" Grid...
I have lots of orders in tblOrders and a few deliveries in tblDeliveries.
SELECT tblOrders.SkuBestelId, Sum(tblDeliveries.delivered) AS TotalDelivered
FROM tblOrders
INNER JOIN tblDeliveries ON tblOrders.SkuBestelId = tblDeliveries.SkuBestelId
GROUP BY tblOrders .SkuBestelId;
Of course, this gives me lots of "TotalDelivered" fields wi...
I got this error when i use sum function in linq.
The cast to value type 'Decimal' failed because the materialized value is null. Either the result type's generic parameter or the query must use a nullable type.
GroupProduct.Where(a => a.Product.ProductID==1).Sum(Content => Content.Amount==null?0:Content.Amount),
...
We've all been there, we have some deep property like cake.frosting.berries.loader that we need to check if it's null so there's no exception. The way to do is is to use a short-circuiting if statement
if (cake != null && cake.frosting != null && cake.frosting.berries != null) ...
This strikes me however as not very elegant, there sh...
considering a pointer to a struct
struct a_struct
{
int A;
};
Is it ok to do :
struct a_struct *ptr;
//...
if( ptr != NULL && ptr->A == 1)
{
//work with ptr struct
}
or should you Test if the pointer is valid before testing for on of its field.
if(ptr != NULL)
{
if(ptr->A == 1)
{
...
I have what seems to be a really easy SQL query I can't figure out and its driving me nuts. This is SQL 2008. Basically, there is a status field where the can pick "pending", "satisfied" or all. If they send in "pending" or "satisfied" there's no problem. But when they pick all I'm having problems. Mostly because I can't figure out how ...
hi
Is there any way to send null to an optional stored procedure parameter via crystal reports8.5 and vb6? I use CRXParamDef.AddCurrentValue method to send stored procedure parameter values.
...
Hi all,
I've mostly only worked with C, and am running into some unfamiliar issues in C++.
Let's say that I have some function like this in C, which would be very typical:
int some_c_function(const char* var)
{
if (var == NULL) {
/* exit early so we don't dereference a null pointer */
}
/* rest of code */
}
and l...
I have some code:
using (OAZISDBDataContext ctx = new OAZISDBDataContext())
{
IEnumerable<DBContactDetail> details = ctx.ExecuteQuery<DBContactDetail>("exec [dbo].[zna_contact] {0}, {1}",
"test", "19601023",
}
However I also want to be able to pass empty ...
Table structure - Data present for 5 min. slots -
data_point | point_date
12 | 00:00
14 | 00:05
23 | 00:10
10 | 00:15
43 | 00:25
10 | 00:40
When I run the query for say 30 mins. and if data is present I'll get 6 rows (one row for each 5 min. stamp). Simple Query -...