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Fast way of counting non-zero bits in positive integer
...nd, gmpy popcount() took about 1/20th of the time of bin(n).count("1"). So if you can install gmpy, use that.
To answer a question in the comments, for bytes I'd use a lookup table. You can generate it at runtime:
counts = bytes(bin(x).count("1") for x in range(256)) # py2: use bytearray
Or jus...
Comparing two dataframes and getting the differences
...rames axes are compared with _indexed_same method, and exception is raised if differences found, even in columns/indices order.
If I got you right, you want not to find changes, but symmetric difference. For that, one approach might be concatenate dataframes:
>>> df = pd.concat([df1, df2]...
Can HTML checkboxes be set to readonly?
...
PS...if you want the checkbox to be in the checked state you need to add checked="checked", not mess with the javascript. The javascript is just there to force mouse clicks to be ignored on the input object, not to set state of th...
Why should I use Deque over Stack?
...ecause it's a subclass of Vector.
Oh, and also Stack has no interface, so if you know you need Stack operations you end up committing to a specific concrete class, which isn't usually a good idea.
Also as pointed out in the comments, Stack and Deque have reverse iteration orders:
Stack<Integer...
Adding minutes to date time in PHP
...
With date: 2011-11-18 00:00 if I add 5 mins, I get 2012-04-18 00:00 as a result. ` $time = new DateTime($_REQUEST['start']); $time->add(new DateInterval('P' . $duration . 'M')); $endTime = $time->format('Y-m-d H:i'); echo $endTime; ` Applogies f...
How to list all the files in a commit?
...d Way (because it's a plumbing command; meant to be programmatic):
$ git diff-tree --no-commit-id --name-only -r bd61ad98
index.html
javascript/application.js
javascript/ie6.js
Another Way (less preferred for scripts, because it's a porcelain command; meant to be user-facing)
$ git show --pretty...
Django connection to PostgreSQL: “Peer authentication failed”
...tead of using unix sockets, you use TCP connections. From django docs:
If you’re using PostgreSQL, by default (empty HOST), the connection to
the database is done through UNIX domain sockets (‘local’ lines in
pg_hba.conf). If you want to connect through TCP sockets, set HOST to
‘lo...
multi-layer perceptron (MLP) architecture: criteria for choosing number of hidden layers and size of
If we have 10 eigenvectors then we can have 10 neural nodes in input layer.If we have 5 output classes then we can have 5 nodes in output layer.But what is the criteria for choosing number of hidden layer in a MLP and how many neural nodes in 1 hidden layer?
...
Python Infinity - Any caveats?
...t returns either 0.0 or inf. So it does work correctly when the input is inifinty, but not when the result should be infinity.
– Abel
May 9 '15 at 14:50
2
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Why do loggers recommend using a logger per class?
...capture the source of the log message (ie. the class writing to the log). If you don't have one logger per class, but instead have one logger for the entire app, you need to resort to more reflection tricks to know where the log messages are coming from.
Compare the following:
Log per class
usi...