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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 exactly does a generator comprehension work?
...s each item out of the expression, one by one.
>>> my_list = [1, 3, 5, 9, 2, 6]
>>> filtered_list = [item for item in my_list if item > 3]
>>> print(filtered_list)
[5, 9, 6]
>>> len(filtered_list)
3
>>> # compare to generator expression
...
>>&...
Counting the occurrences / frequency of array elements
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36 Answers
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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...
python list by value not by reference [duplicate]
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answered Jan 5 '12 at 14:30
phihagphihag
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Selecting last element in JavaScript array [duplicate]
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Convert a byte array to integer in Java and vice versa
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235
Use the classes found in the java.nio namespace, in particular, the ByteBuffer. It can do all ...
How do I detect if Python is running as a 64-bit application? [duplicate]
...k with the windows registry. Depending on whether you're running python as 32-bit or 64-bit, the key value will be different. How do I detect if Python is running as a 64-bit application as opposed to a 32-bit application?
...
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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How can I get list of values from dict?
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539
Yes it's the exact same thing in Python 2:
d.values()
In Python 3 (where dict.values returns...