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Find the max of two or more columns with pandas
...df = pd.DataFrame({"A": [1,2,3], "B": [-2, 8, 1]})
>>> df
A B
0 1 -2
1 2 8
2 3 1
>>> df[["A", "B"]]
A B
0 1 -2
1 2 8
2 3 1
>>> df[["A", "B"]].max(axis=1)
0 1
1 8
2 3
and so:
>>> df["C"] = df[["A", "B"]].max(axis=1)
>>> df
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How do I get indices of N maximum values in a NumPy array?
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edited Aug 2 '11 at 10:45
answered Aug 2 '11 at 10:32
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How do I cast a string to integer and have 0 in case of error in the cast with PostgreSQL?
...hould work:
SELECT CASE WHEN myfield~E'^\\d+$' THEN myfield::integer ELSE 0 END FROM mytable;
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Convert an image to grayscale in HTML/CSS
.../* Disable grayscale on hover */
img:hover {
-webkit-filter: grayscale(0);
filter: none;
}
<img src="http://lorempixel.com/400/200/">
What about Internet Explorer 10?
You can use a polyfill like gray.
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How many double numbers are there between 0.0 and 1.0?
...e), there will therefore be 2 to the 52th power different doubles (i.e., 4503599627370496 of them). For example, that's the number of distinct doubles between 0.5 included and 1.0 excluded, and exactly that many also lie between 1.0 included and 2.0 excluded, and so forth.
Counting the doubles bet...
CSS triangle custom border color
...th 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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From ND to 1D arrays
...c = a.flatten()
If you just want an iterator, use np.ndarray.flat:
In [20]: d = a.flat
In [21]: d
Out[21]: <numpy.flatiter object at 0x8ec2068>
In [22]: list(d)
Out[22]: [1, 2, 3, 4, 5, 6]
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pyplot scatter plot marker size
...xamples and the output they produce.
# doubling the width of markers
x = [0,2,4,6,8,10]
y = [0]*len(x)
s = [20*4**n for n in range(len(x))]
plt.scatter(x,y,s=s)
plt.show()
gives
Notice how the size increases very quickly. If instead we have
# doubling the area of markers
x = [0,2,4,6,8,10]
y ...
Why is January month 0 in Java Calendar?
In java.util.Calendar , January is defined as month 0, not month 1. Is there any specific reason to that ?
16 Answers
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Sort a list by multiple attributes?
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edited Apr 24 '18 at 22:05
smci
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