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Print a list in reverse order with range()?
...te:
If you want to use only range to achieve the same result, you can use all its parameters. range(start, stop, step)
For example, to generate a list [5,4,3,2,1,0], you can use the following:
range(5, -1, -1)
It may be less intuitive but as the comments mention, this is more efficient and the ...
How to find where gem files are installed
I can finds gems that are installed using gem list , but it doesn't show me where the gems are installed.
10 Answers
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Setting the selected value on a Django forms.ChoiceField
...rying to assign the selected value to a ChoiceField.
If you have already called super().__init__ in your Form class, you should update the form.initial dictionary, not the field.initial property. If you study form.initial (e.g. print self.initial after the call to super().__init__), it will contai...
Express-js can't GET my static files, why?
...
In case of new install you should verify that your express module is properly installed (expressjs.com/en/starter/installing.html) then you should check the path and your directory name like Giacomo said ;)
– Spl2nky
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What's wrong with nullable columns in composite primary keys?
...
Primary keys are for uniquely identifying rows. This is done by comparing all parts of a key to the input.
Per definition, NULL cannot be part of a successful comparison. Even a comparison to itself (NULL = NULL) will fail. This means a key containing NULL would not work.
Additonally, NULL is al...
Fastest Way to Serve a File Using PHP
...erywhere.
Using the X-SendFile header
As documented by others it's actually the best way. The basis is that you do your access control in php and then instead of sending the file yourself you tell the web server to do it.
The basic php code is :
header("X-Sendfile: $file_name");
header("Conten...
Proper way to use **kwargs in Python
...*kwargs):
...etc...
this is not true. In the latter case, f can be called as f(23, 42), while the former case accepts named arguments only -- no positional calls. Often you want to allow the caller maximum flexibility and therefore the second form, as most answers assert, is preferable: but ...
How to pattern match using regular expression in Scala?
...ter match {
case Pattern(c) => c bound to capture group here
case _ =>
}
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In Python, how do I index a list with another list?
...ng, either by integer, slice or index-list:
class Flexlist(list):
def __getitem__(self, keys):
if isinstance(keys, (int, slice)): return list.__getitem__(self, keys)
return [self[k] for k in keys]
Which, for your example, you would use as:
L = Flexlist(['a', 'b', 'c', 'd', 'e...
Listen for key press in .NET console app
...
Use Console.KeyAvailable so that you only call ReadKey when you know it won't block:
Console.WriteLine("Press ESC to stop");
do {
while (! Console.KeyAvailable) {
// Do something
}
} while (Console.ReadKey(true).Key != ConsoleKey.Escape);
...