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What is the purpose of the single underscore “_” variable in Python?
...cate that part
of a function result is being deliberately ignored (Conceptually, it is being discarded.), as in code like:
label, has_label, _ = text.partition(':').
As part of a function definition (using either def or lambda), where
the signature is fixed (e.g. by a callback or parent class API), ...
Or versus OrElse
...oth terms. When temp Is DBNull.Value, it can't be compared to zero, so it falls over.
You should use... well, whichever one makes sense.
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Getting Django admin url for an object
...e was an easy way to get the admin url of an object, and I had written a small filter that I'd use like this: <a href="{{ object|admin_url }}" .... > ... </a>
...
DataTrigger where value is NOT null?
...
I'm using this to only enable a button if a listview item is selected (ie not null):
<Style TargetType="{x:Type Button}">
<Setter Property="IsEnabled" Value="True"/>
<Style.Triggers>
<DataTrigger Binding="{Binding ElementName=lvMyList, Path=Selecte...
Python (and Python C API): __new__ versus __init__
...vs immutable types.
__new__ accepts a type as the first argument, and (usually) returns a new instance of that type. Thus it is suitable for use with both mutable and immutable types.
__init__ accepts an instance as the first argument and modifies the attributes of that instance. This is inappropr...
Python multiprocessing pool.map for multiple arguments
...rmap method, which accepts a sequence of argument tuples. It then automatically unpacks the arguments from each tuple and passes them to the given function:
import multiprocessing
from itertools import product
def merge_names(a, b):
return '{} & {}'.format(a, b)
if __name__ == '__main__':...
Parse a .py file, read the AST, modify it, then write back the modified source code
I want to programmatically edit python source code. Basically I want to read a .py file, generate the AST , and then write back the modified python source code (i.e. another .py file).
...
fs: how do I locate a parent folder?
...
why? just generally why? can someone please explain?
– eyurdakul
May 16 '17 at 15:12
...
PHP function overloading
...um_args() and func_get_arg() to get the arguments passed, and use them normally.
For example:
function myFunc() {
for ($i = 0; $i < func_num_args(); $i++) {
printf("Argument %d: %s\n", $i, func_get_arg($i));
}
}
/*
Argument 0: a
Argument 1: 2
Argument 2: 3.5
*/
myFunc('a', 2, 3...
Understanding Python super() with __init__() methods [duplicate]
...can be nice. But the main advantage comes with multiple inheritance, where all sorts of fun stuff can happen. See the standard docs on super if you haven't already.
Note that the syntax changed in Python 3.0: you can just say super().__init__() instead of super(ChildB, self).__init__() which IMO is...