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How to add a new row to an empty numpy array
...append(arr, np.array([[1,2,3]]), axis=0)
arr = np.append(arr, np.array([[4,5,6]]), axis=0)
But, @jonrsharpe is right. In fact, if you're going to be appending in a loop, it would be much faster to append to a list as in your first example, then convert to a numpy array at the end, since you're re...
Merge Images Side by Side(Horizontally)
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What is IP address '::1'?
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::1 is the loopback address in IPv6. Think of it as the IPv6 version of 127.0.0.1.
See http:/...
Pandas dataframe get first row of each group
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Shell equality operators (=, ==, -eq)
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edited Dec 5 '19 at 16:59
answered Dec 8 '13 at 3:31
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Sorting arrays in NumPy by column
...turn a copy:
In [1]: import numpy as np
In [2]: a = np.array([[1,2,3],[4,5,6],[0,0,1]])
In [3]: np.sort(a.view('i8,i8,i8'), order=['f1'], axis=0).view(np.int)
Out[3]:
array([[0, 0, 1],
[1, 2, 3],
[4, 5, 6]])
To sort it in-place:
In [6]: a.view('i8,i8,i8').sort(order=['f1'], axis...
CSS triangle custom border color
...with a 1px border (around the angled sides of the triangle) with color #CAD5E0. Is this possible? Here's what I have so far:
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Why is a round-trip conversion via a string not safe for a double?
...}
*dst = 0;
}
}
It turns out that _ecvt returns the string 845512408225570.
Notice the trailing zero? It turns out that makes all the difference!
When the zero is present, the result actually parses back to 0.84551240822557006, which is your original number -- so it compares equal, an...
How can I obtain the element-wise logical NOT of a pandas Series?
...st of 3: 91.8 µs per loop
In [11]: %timeit ~s
10000 loops, best of 3: 73.5 µs per loop
In [12]: %timeit (-s)
10000 loops, best of 3: 73.5 µs per loop
As of Pandas 0.13.0, Series are no longer subclasses of numpy.ndarray; they are now subclasses of pd.NDFrame. This might have something to do w...