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How to filter Pandas dataframe using 'in' and 'not in' like in SQL
...g.isin(somewhere)
Or for "NOT IN": ~something.isin(somewhere)
As a worked example:
import pandas as pd
>>> df
country
0 US
1 UK
2 Germany
3 China
>>> countries_to_keep
['UK', 'China']
>>> df.country.isin(countries_to_keep)
0 False
1 True
2 ...
How to extract the n-th elements from a list of tuples?
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n = 1 # N. . .
[x[n] for x in elements]
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Convert light frequency to RGB?
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Here's a detailed explanation of the entire conversion process: http://www.fourmilab.ch/documents/specrend/. Source code included!
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Python nested functions variable scoping [duplicate]
...the statement b = 4 commented out, this code outputs 0 1, just what you'd expect.
But if you uncomment that line, on the line print b, you get the error
UnboundLocalError: local variable 'b' referenced before assignment
It seems mysterious that the presence of b = 4 might somehow make b disappea...
How to remove leading and trailing zeros in a string? Python
...12-n\n"," 12091231000-n00000","alphanum0000", "00alphanum"]
pred = lambda x: x in {"0", "\n", " "}
list("".join(mit.strip(i, pred)) for i in iterables)
# ['231512-n', '12091231000-n', 'alphanum', 'alphanum']
Details
Notice, here we strip both leading and trailing "0"s among other elements that...
How to check if all list items have the same value and return it, or return an “otherValue” if they
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var val = yyy.First().Value;
return yyy.All(x=>x.Value == val) ? val : otherValue;
Cleanest way I can think of. You can make it a one-liner by inlining val, but First() would be evaluated n times, doubling execution time.
To incorporate the "empty set" behavior ...
Is it possible to set code behind a resource dictionary in WPF for event handling?
Is it possible to set code behind a resource dictionary in WPF. For example in a usercontrol for a button you declare it in XAML. The event handling code for the button click is done in the code file behind the control. If I was to create a data template with a button how can I write the event handl...
ValueError: setting an array element with a sequence
... array from a list that isn't shaped like a multi-dimensional array. For example
numpy.array([[1,2], [2, 3, 4]])
or
numpy.array([[1,2], [2, [3, 4]]])
will yield this error message, because the shape of the input list isn't a (generalised) "box" that can be turned into a multidimensional array...
'and' (boolean) vs '&' (bitwise) - Why difference in behavior with lists vs numpy arrays?
What explains the difference in behavior of boolean and bitwise operations on lists vs NumPy arrays?
8 Answers
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rgdal package installation
The issue here is not exactly how to plot maps through R, as I have found already a pretty nice example here , but rather how to make it work. In fact, I am unable to load library rgdal :
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