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How to filter Pandas dataframe using 'in' and 'not in' like in SQL
...andas 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 False
3 True
Name: country, dtype: bool
>>> df[df.country.isin(countries_to_ke...
Why is pow(a, d, n) so much faster than a**d % n?
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edited Jan 3 '13 at 6:08
answered Jan 3 '13 at 6:03
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Markdown: continue numbered list
In the following markdown code I want item 3 to start with list number 3. But because of the code block in between markdown starts this list item as a new list. Is there any way to prevent that behaviour?
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How to update Python?
...will stop receiving official updates from python.org in 2020. Also, Python-3.7 has been released. Check out Python-Future on how to make your Python-2 code compatible with Python-3. For updating conda, the documentation now recommends using conda update --all in each of your conda environments to up...
jQuery select by attribute using AND and OR operators
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AND operation
a=$('[myc="blue"][myid="1"][myid="3"]');
OR operation, use commas
a=$('[myc="blue"],[myid="1"],[myid="3"]');
As @Vega commented:
a=$('[myc="blue"][myid="1"],[myc="blue"][myid="3"]');
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How do you get the magnitude of a vector in Numpy?
...ray -- say x.norm() -- but oh well).
import numpy as np
x = np.array([1,2,3,4,5])
np.linalg.norm(x)
You can also feed in an optional ord for the nth order norm you want. Say you wanted the 1-norm:
np.linalg.norm(x,ord=1)
And so on.
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The $.param( ) inverse function in JavaScript / jQuery
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answered Jun 9 '11 at 19:23
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How to delete multiple values from a vector?
...vector like: a = c(1:10) and I need to remove multiple values, like: 2, 3, 5
8 Answers
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Compare two data.frames to find the rows in data.frame 1 that are not present in data.frame 2
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13 Answers
13
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Split comma-separated strings in a column into separate rows
...th more than about 5000 rows, Jaap's data.table method 2 and the variant DT3 are the fastest, magnitudes faster than the slowest methods.
Remarkably, the timings of the two tidyverse methods and the splistackshape solution are so similar that it's difficult to distiguish the curves in the chart. T...