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What is the preferred/idiomatic way to insert into a map?
... which you assign a value. Obviously, this can be inefficient if the mapped_type can benefit from being directly initialized instead of default constructed and assigned. This method also makes it impossible to determine if an insertion has indeed taken place or if you have only overwritten the value...
Capturing Groups From a Grep RegEx
...e using Bash, you don't even have to use grep:
files="*.jpg"
regex="[0-9]+_([a-z]+)_[0-9a-z]*"
for f in $files # unquoted in order to allow the glob to expand
do
if [[ $f =~ $regex ]]
then
name="${BASH_REMATCH[1]}"
echo "${name}.jpg" # concatenate strings
name=...
import module from string variable
...
The __import__ function can be a bit hard to understand.
If you change
i = __import__('matplotlib.text')
to
i = __import__('matplotlib.text', fromlist=[''])
then i will refer to matplotlib.text.
In Python 2.7 and Python ...
What does [:] mean?
...ctly create slice() objects. If you need them anyway, NumPy provides the s_ helper as an alternative way to create them.
– Sven Marnach
Apr 7 '14 at 10:20
...
How to add property to a class dynamically?
...ibute, on a given class. Kinda like a way to factor a huge if tree out of __getattribute__.
When I ask for foo.b in the example above, Python sees that the b defined on the class implements the descriptor protocol—which just means it's an object with a __get__, __set__, or __delete__ method. Th...
What does this mean: Failure [INSTALL_FAILED_CONTAINER_ERROR]?
I try to deploy my app and sometimes get this error:
14 Answers
14
...
How to make my custom type to work with “range-based for loops”?
...C++ standard, is specified to expand to something equivalent to:
for( range_declaration : range_expression )
becomes:
{
auto && __range = range_expression ;
for (auto __begin = begin_expr,
__end = end_expr;
__begin != __end; ++__begin) {
range_declaration = *...
What does it mean if a Python object is “subscriptable” or not?
...
It basically means that the object implements the __getitem__() method. In other words, it describes objects that are "containers", meaning they contain other objects. This includes strings, lists, tuples, and dictionaries.
...
Is int[] a reference type or a value type?
...ways reference types
which are allocated on the managed
heap, and your app's variable contains
a reference to the array and not the
array itself.
https://msdn.microsoft.com/en-us/library/bb985948.aspx
share
...
Are there legitimate uses for JavaScript's “with” statement?
... same technique used elsewhere - the Chromium source code!
InjectedScript._evaluateOn = function(evalFunction, object, expression) {
InjectedScript._ensureCommandLineAPIInstalled();
// Surround the expression in with statements to inject our command line API so that
// the window object...