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void in C# generics?
...nctions need to return null, but if it unifies your code, it should be a small price to pay.
This inability to use void as a return type is at least partially responsible for a split between the Func<...> and Action<...> families of generic delegates: had it been possible to return void...
How do I pass the value (not the reference) of a JS variable to a function? [duplicate]
...selection(i);
});
})(i);
}
By creating an anonymous function and calling it with the variable as the first argument, you're passing-by-value to the function and creating a closure.
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What does the [Flags] Enum Attribute mean in C#?
... Such collections are often used with bitwise operators, for example:
var allowedColors = MyColor.Red | MyColor.Green | MyColor.Blue;
Note that the [Flags] attribute doesn't enable this by itself - all it does is allow a nice representation by the .ToString() method:
enum Suits { Spades = 1, Clu...
How do I add indices to MySQL tables?
...
ALTER TABLE `table` ADD INDEX `product_id_index` (`product_id`)
Never compare integer to strings in MySQL. If id is int, remove the quotes.
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How can I determine if a variable is 'undefined' or 'null'?
...enceError and break execution if variable is not defined or referred to at all in the code, using typeof is safer.
– Mani Gandham
Jun 15 '14 at 9:49
59
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jQuery Validate - Enable validation for hidden fields
...ry, this could break an existing
setup. In the unlikely case that it actually does, you can fix it by
setting the ignore-option to “[]” (square brackets without the
quotes)."
To change this setting for all forms:
$.validator.setDefaults({
ignore: [],
// any other default option...
How to get JQuery.trigger('click'); to initiate a mouse click
... if one of the hrefs on the <a tag is '#', that would do it. <a normally redirects to a different URL. You must stop it with ev.preventDefault() and ev.stopPropagation() before your click handler returns. OR, use some other tag besides <a; you can attach click handlers to anything that's...
adding multiple entries to a HashMap at once in one statement
... 2016) as follow:
Map<String, Integer> cities = Map.of("Brussels", 1_139000, "Cardiff", 341_000);
The var-args case for Map is a little bit harder, you need to have both keys and values, but in Java, methods can’t have two var-args parameters. So the general case is handled by taking a va...
Summarizing multiple columns with dplyr? [duplicate]
...
The dplyr package contains summarise_all for this aim:
library(dplyr)
df %>% group_by(grp) %>% summarise_all(list(mean))
#> # A tibble: 3 x 5
#> grp a b c d
#> <int> <dbl> <dbl> <dbl> <dbl>
#>...
Is there some way to PUSH data from web server to browser?
...
Yes, what you're looking for is COMET http://en.wikipedia.org/wiki/Comet_(programming). Other good Google terms to search for are AJAX-push and reverse-ajax.
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