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Why is it slower to iterate over a small string than a small list?
...nd with timeit and noticed that doing a simple list comprehension over a small string took longer than doing the same operation on a list of small single character strings. Any explanation? It's almost 1.35 times as much time.
...
Should all Python classes extend object?
...inheritance are different in ways that I won't even try to summarize here. All good documentation that I've seen about MI describes new-style classes.
Finally, old-style classes have disappeared in Python 3, and inheritance from object has become implicit. So, always prefer new style classes unless...
What does $_ mean in PowerShell?
...
This is the variable for the current value in the pipe line, which is called $PSItem in Powershell 3 and newer.
1,2,3 | %{ write-host $_ }
or
1,2,3 | %{ write-host $PSItem }
For example in the above code the %{} block is called for every value in the array. The $_ or $PSItem variable ...
Forced naming of parameters in Python
...(10, forcenamed=20)
10 20
>>> foo(10, 20)
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
TypeError: foo() takes exactly 1 positional argument (2 given)
This can also be combined with **kwargs:
def foo(pos, *, forcenamed, **kwargs):
...
What is the JSF resource library for and how should it be used?
...
Actually, all of those examples on the web wherein the common content/file type like "js", "css", "img", etc is been used as library name are misleading.
Real world examples
To start, let's look at how existing JSF implementati...
How do you query for “is not null” in Mongo?
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This will return all documents with a key called "IMAGE URL", but they may still have a null value.
db.mycollection.find({"IMAGE URL":{$exists:true}});
This will return all documents with both a key called "IMAGE URL" and a non-null value.
d...
How can I filter a date of a DateTimeField in Django?
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Much better than all of the other answers here, thanks!
– Kin
Jan 6 '14 at 17:06
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How to Update Multiple Array Elements in mongodb
...At this moment it is not possible to use the positional operator to update all items in an array. See JIRA http://jira.mongodb.org/browse/SERVER-1243
As a work around you can:
Update each item individually
(events.0.handled events.1.handled
...) or...
Read the document, do the edits
manually and ...
How to set child process' environment variable in Makefile
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I have GNU make 3.81, and all: <\n\t>export PROJ_ROOT=$(CURDIR)<\n\t>echo $(PROJ_ROOT)<\n> outputs the correct expansion for the first row, but only echo for the second one. PROJ_ROOT is not set after running make. Spaces around = gi...
How to fix “Attempted relative import in non-package” even with __init__.py
...ry to execute the above shell command, the fact that you need __init__.pys all the way down, and the __package__-modifying trickery (described below by BrenBarn) needed to allow these imports for executable scripts (e.g. when using a shebang and doing ./my_script.py at the Unix shell) would all be u...