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Replace all elements of Python NumPy Array that are greater than some value
...o replace all values in it greater than or equal to a threshold T with 255.0. To my knowledge, the most fundamental way would be:
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Multiple aggregations of the same column using pandas GroupBy.agg()
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You can simply pass the functions as a list:
In [20]: df.groupby("dummy").agg({"returns": [np.mean, np.sum]})
Out[20]:
mean sum
dummy
1 0.036901 0.369012
or as a dictionary:
In [21]: df.groupby('dummy').agg({'returns':
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Suppress Scientific Notation in Numpy When Creating Array From Nested List
...ons(suppress=True), for details see here:
http://pythonquirks.blogspot.fr/2009/10/controlling-printing-in-numpy.html
For SciPy.org numpy documentation, which includes all function parameters (suppress isn't detailed in the above link), see here: https://docs.scipy.org/doc/numpy/reference/generated/...
Conditional Replace Pandas
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.ix indexer works okay for pandas version prior to 0.20.0, but since pandas 0.20.0, the .ix indexer is deprecated, so you should avoid using it. Instead, you can use .loc or iloc indexers. You can solve this problem by:
mask = df.my_channel > 20000
column_name = 'my_chann...
What's the idiomatic syntax for prepending to a short python list?
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The s.insert(0, x) form is the most common.
Whenever you see it though, it may be time to consider using a collections.deque instead of a list.
share
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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 ...
How to get first character of string?
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1080
What you want is charAt.
var x = 'some string';
alert(x.charAt(0)); // alerts 's'
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Detect if Visual C++ Redistributable for Visual Studio 2012 is installed
How to detect if Visual C++ Redistributable for Visual Studio 2012 is installed?
20 Answers
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Matplotlib discrete colorbar
...rm as normalizer for your scatter. The quirky bit (in my method) is making 0 showup as grey.
For images i often use the cmap.set_bad() and convert my data to a numpy masked array. That would be much easier to make 0 grey, but i couldnt get this to work with the scatter or the custom cmap.
As an ...
Warning: Null value is eliminated by an aggregate or other SET operation in Aqua Data Studio
...ult is display.
How to solve this problem?. How to change the null data to 0 when no data in the table?.
6 Answers
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