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Why are floating point numbers inaccurate?
...icand). A very simple number, say 9.2, is actually this fraction:
5179139571476070 * 2 -49
Where the exponent is -49 and the mantissa is 5179139571476070. The reason it is impossible to represent some decimal numbers this way is that both the exponent and the mantissa must be integers. In othe...
How do I break out of a loop in Perl?
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answered Nov 19 '08 at 20:23
Zain RizviZain Rizvi
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How do I find the location of Python module sources?
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382
For a pure python module you can find the source by looking at themodule.__file__.
The datetim...
Writing to an Excel spreadsheet
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answered Nov 18 '12 at 5:32
thkangthkang
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Appending to an empty DataFrame in Pandas?
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3 Answers
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Active
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Creating range in JavaScript - strange syntax
...0); //true
arr[0]; //'a'
Object.keys(arr); //['0', '1', '2']
arr.length; //3, implies arr[3] === undefined
//we expand the array by 1 item
arr.length = 4;
arr[3]; //undefined
arr.hasOwnProperty(3); //false
Object.keys(arr); //['0', '1', '2']
We get to the inherent difference between the number of...
Can a for loop increment/decrement by more than one?
...in Javascript besides i++ and ++i ? For example, I want to increment by 3 instead of one.
7 Answers
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Does the C++ standard mandate poor performance for iostreams, or am I just dealing with a poor imple
...ble to remove some of these
inefficiencies. This is discussed in
§6.2.3 and §6.2.5.
Since the report was written in 2006 one would hope that many of the recommendations would have been incorporated into current compilers, but perhaps this is not the case.
As you mention, facets may not feat...
numpy: most efficient frequency counts for unique values in an array
...ncount(x)
ii = np.nonzero(y)[0]
And then:
zip(ii,y[ii])
# [(1, 5), (2, 3), (5, 1), (25, 1)]
or:
np.vstack((ii,y[ii])).T
# array([[ 1, 5],
[ 2, 3],
[ 5, 1],
[25, 1]])
or however you want to combine the counts and the unique values.
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Correct way to define C++ namespace methods in .cpp file
...se it shows that in the namespace, you are defining the function.
Version 3 is right also because you used the :: scope resolution operator to refer to the MyClass::method () in the namespace ns1. I prefer version 3.
See Namespaces (C++). This is the best way to do this.
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