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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...
When is it acceptable to call GC.Collect?
...bjects - particularly those you suspect to be in generations 1 and 2 - are now eligible for garbage collection, and that now would be an appropriate time to collect in terms of the small performance hit.
A good example of this is if you've just closed a large form. You know that all the UI controls...
Rails find_or_create_by more than one attribute?
...ind_or_create_by_member_id_and_group_id(4, 7)
(use find_or_initialize_by if you don't want to save the record right away)
Edit: The above method is deprecated in Rails 4. The new way to do it will be:
GroupMember.where(:member_id => 4, :group_id => 7).first_or_create
and
GroupMember.whe...
Open multiple Eclipse workspaces on the Mac
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But now I can't close the terminal window until I close eclipse
– Blundell
Jul 5 '12 at 7:37
1
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PostgreSQL: Show tables in PostgreSQL
... list all databases and users by \l command, (list other commands by \?).
Now if you want to see other databases you can change user/database by \c command like \c template1, \c postgres postgres and use \d, \dt or \dS to see tables/views/etc.
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extract part of a string using bash/cut/split
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I'm not sure if this is an argument for or against the creative use of grep, but try it with VAR=/here/is/a/path:with/a/colon/inside:DNS9=domain.com
– rici
Oct 20 '13 at 21:51
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What is the maximum possible length of a .NET string?
...estion as far as I can see, so an authoritative answer might require some knowledge of internals. Would the maximum change on a 64-bit system?
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Which characters are valid/invalid in a JSON key name?
...d key. It can even have " as long as you escape it:
{"The \"meaning\" of life":42}
There is perhaps a chance you'll encounter difficulties loading such values into some languages, which try to associate keys with object field names. I don't know of any such cases, however.
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How to read and write into file using JavaScript?
...ion on the Javascript File class
Edit: That link was to the Sun docs that now have been moved by Oracle.
To keep up with the times here's the node.js documentation for the FileSystem class: http://nodejs.org/docs/latest/api/fs.html
Edit(2): You can read files client side now with HTML5: http://ww...
Difference between Destroy and Delete
What is the difference between
6 Answers
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