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How to generate all permutations of a list?
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Combination (order does NOT matter):
print list(itertools.combinations('123', 2))
[('1', '2'), ('1', '3'), ('2', '3')]
Cartesian product (with several iterables):
print list(itertools.product([1,2,3], [4,5,6]))
[(1, 4), (1, 5), (1, 6),
(2, 4), (2, 5), (2, 6),
(3, 4), (3, 5), (3, 6)]
Cartesia...
How do I parse a string to a float or int?
...temptible lie
False True So false it becomes true
"123.456" True Decimal
" -127 " True Spaces trimmed
"\t\n12\r\n" True whitespace ignored
"NaN" True Not a number
"NaNanananaBATMAN" False ...
http HEAD vs GET performance
...EAD might work nicely.
For example, suppose you want to check if resource 123 exists. A 200 means "yes" and a 404 means "no":
HEAD /resources/123 HTTP/1.1
[...]
HTTP/1.1 404 Not Found
[...]
However, if the "yes" or "no" you want from your REST service is a part of the resource itself, rather th...
jQuery Data vs Attr?
...you'll need to use .attr():
HTML:
<a id="foo" href="#" data-color="ABC123"></a>
<a id="bar" href="#" data-color="654321"></a>
JS:
$('#foo').data('color').length; //6
$('#bar').data('color').length; //undefined, length isn't a property of numbers
$('#foo').attr('data-col...
Normalizing mousewheel speed across browsers
For a different question I composed this answer , including this sample code .
10 Answers
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What is the difference between Swing and AWT?
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AWT is a Java interface to native system GUI code present in your OS. It will not work the same on every system, although it tries.
Swing is a more-or-less pure-Java GUI. It uses AWT to create an operating system window and then paints pictures of buttons, labels, text, checkboxes, etc., i...
How do I remove the “extended attributes” on a file in Mac OS X?
... script that runs a stress test. Part of the test is to open, save, and close certain files. Somehow, the files have picked up some "extended attributes" that prohibit the files from being saved. That causes the stress test to fail.
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How do I perform an insert and return inserted identity with Dapper?
...Username = "lorem ipsum",
Phone = "555-123",
Email = "lorem ipsum"
},
tran);
Return inserted object with ID:
If you wanted you could get Phone and Email or even th...
Strangest language feature
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Or, more usefully, "0123456789abcdef"[x & 0xf]
– Dipstick
Jan 3 '10 at 15:33
17
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Finding Number of Cores in Java
...ly available to the JVM (at startup I guess). Using CPU affinity the user/OS can restrict the number of "cores" a JVM sees. You can even do it on a running JVM but I'm not too sure how this influence availableProcessors().
– SyntaxT3rr0r
Jan 21 '11 at 16:17
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