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Understanding exactly when a data.table is a reference to (vs a copy of) another data.table
....table, too. The := isn't for doing that. So the following is a deliberate error as := isn't for just binding object names :
DT2 := DT # not what := is for, not defined, gives a nice error
:= is for subassigning by reference. But you don't use it like you would in base :
DT[3,"foo"] := newval...
In Firebase, is there a way to get the number of children of a node without loading all the node dat
...tead of event we now have change and context.
The given example throws an error complaining that event.data is undefined. This pattern seems to work better:
exports.countPrescriptions = functions.database.ref(`/prescriptions`).onWrite((change, context) => {
const data = change.after.val();
...
Keyword for the outer class from an anonymous inner class [duplicate]
...thod. But if you try to use "a.this" in that case, you will get a compiler error.
– rents
Apr 16 '17 at 21:03
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SQL to LINQ Tool [closed]
...½ years. I could not even install Linqer correctly. Failed on me with an error: "Not suppported Entity Framework version 0", spelling mistake & all.
– user1040323
Sep 28 '18 at 15:00
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c# why can't a nullable int be assigned null as a value [duplicate]
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Did you actually try this? It should give the error "Cannot implicitly convert type 'object' to 'int?'. An explicit conversion exists (are you missing a cast?)"
– Ben Voigt
Sep 7 '16 at 18:01
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Getting the Value of a UITextField as keystrokes are entered?
...extField:) forControlEvents:UIControlEventEditingChanged];
...
// TODO: error checking
- (void)updateLabelUsingContentsOfTextField:(id)sender {
greetingLabel.text = [NSString stringWithFormat:@"Hello %@", ((UITextField *)sender).text];
}
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How do I check if an object has a key in JavaScript? [duplicate]
...perty('myKey');
Note: If you are using ESLint, the above may give you an error for violating the no-prototype-builtins rule, in that case the workaround is as below:
Object.prototype.hasOwnProperty.call(myObj, 'myKey');
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jQuery: $().click(fn) vs. $().bind('click',fn);
...mouseenter,mouseleave," +
"change,select,submit,keydown,keypress,keyup,error").split(","), function(i, name){
// Handle event binding
jQuery.fn[name] = function(fn){
return fn ? this.bind(name, fn) : this.trigger(name);
};
});
So no, there's no difference -
$().click(fn)...
How to get a path to the desktop for current user in C#?
...onment.SpecialFolder.Desktop);
string extension = ".log";
filePath += @"\Error Log\" + extension;
if (!Directory.Exists(filePath))
{
Directory.CreateDirectory(filePath);
}
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improv...
How do I forward declare an inner class? [duplicate]
...in()
{
Foo f;
Container::Inner i;
f.Read(i); // ok
f.Read(3); // error
}
Hopefully, this idiom might be of some use to you (and hopefully your compiler is EDG-based and implements export ;) ).
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