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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 ...
What REALLY happens when you don't free after malloc?
...ram exits. The only exception I can think of might be something like Palm OS where the program's static storage and runtime memory are pretty much the same thing, so not freeing might cause the program to take up more storage. (I'm only speculating here.)
So generally, there's no harm in it, exce...
Why is a combiner needed for reduce method that converts type in java 8
... answered Sep 4 '15 at 7:39
quiz123quiz123
3655 bronze badges
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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...
Find the files existing in one directory but not in the other [closed]
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Explanation:
diff -r dir1 dir2 shows which files are only in dir1 and those only in dir2 and also the changes of the files present in both directories if any.
diff -r dir1 dir2 | grep dir1 shows which files are only in dir1
awk to print only filename.
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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...
What is Linux’s native GUI API?
Both Windows (Win32 API) and OS X (Cocoa) have their own APIs to handle windows, events and other OS stuff. I have never really got a clear answer as to what Linux’s equivalent is?
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postgresql port confusion 5433 or 5432?
I have installed postgresql on OSX. When I run psql, I get
7 Answers
7
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Installing libv8 gem on OS X 10.9+
I'm trying to install libv8 3.16.14.3 but getting an error on OSX Mavericks using latest stable rvm and ruby-1.9.3-p125.
20...