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Inheritance and Overriding __init__ in python
...
The book is a bit dated with respect to subclass-superclass calling. It's also a little dated with respect to subclassing built-in classes.
It looks like this nowadays:
class FileInfo(dict):
"""store file metadata"""
def __init__(self, filename=None):
super(FileInfo,...
Convert .pem to .crt and .key
... is used instead.
-engine id
specifying an engine (by its unique id string) will cause rsa to attempt to obtain a functional reference to the specified engine, thus initialising it if needed. The engine will then be set as the default for all available algorithms.
NOTES
The PEM private key ...
How to create an empty file at the command line in Windows?
...ll cause the
variable used to remain unchanged. As usual with set/p, the string to the
right of the equal sign is displayed as a prompt with no CRLF.
Since here the "string to the right of the equal sign" is empty... the result is an empty file.
The difference with cd. > filename (which...
Differences between Emacs and Vim
...ared to using a GUI editor/IDE and using something like python/awk/etc for extra tasks is up to you.
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What is the id( ) function used for?
... Python objects.
Is it the same with memory addresses in C?
Conceptually, yes, in that they are both guaranteed to be unique in their universe during their lifetime. And in one particular implementation of Python, it actually is the memory address of the corresponding C object.
If yes, wh...
ASP.NET MVC: Is Controller created for every request?
...er == null)
{
throw new InvalidOperationException(
String.Format(
CultureInfo.CurrentCulture,
MvcResources.ControllerBuilder_FactoryReturnedNull,
factory.GetType(),
controllerName));
}
}
Here's the Controll...
Postgres and Indexes on Foreign Keys and Primary Keys
...le, you will have an index on the PK and probably don't need to create any extra indexes.
While it's usually a good idea to create an index on (or including) your referencing-side foreign key columns, it isn't required. Each index you add slows DML operations down slightly, so you pay a performance...
Does the 'mutable' keyword have any purpose other than allowing the variable to be modified by a con
...l state such as a cache. For example:
class HashTable
{
...
public:
string lookup(string key) const
{
if(key == lastKey)
return lastValue;
string value = lookupInternal(key);
lastKey = key;
lastValue = value;
return value;
}
priv...
Clear Text Selection with JavaScript
...ve created a full working example based on your suggestion but adding some extras jsfiddle.net/mkrivan/hohx4nes The most important line is window.getSelection().addRange(document.createRange()); Without this IE does not deselect text in some conditions. And I have changed the ordering of the method ...
URLWithString: returns nil
it may be very easy, but I don't seems to find out why is URLWithString: returning nil here.
7 Answers
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