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How do you extract a column from a multi-dimensional array?
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234
>>> import numpy as np
>>> A = np.array([[1,2,3,4],[5,6,7,8]])
>>> ...
Uninitialized constant ActiveSupport::Dependencies::Mutex (NameError)
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137
This is an incompatibility between Rails 2.3.8 and recent versions of RubyGems. Upgrade to the ...
How to insert newline in string literal?
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323
Well, simple options are:
string.Format:
string x = string.Format("first line{0}second line...
Pandas dataframe get first row of each group
...;> df.groupby('id').first()
value
id
1 first
2 first
3 first
4 second
5 first
6 first
7 fourth
If you need id as column:
>>> df.groupby('id').first().reset_index()
id value
0 1 first
1 2 first
2 3 first
3 4 second
4 5 first
5 6...
Python, compute list difference
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373
If the order does not matter, you can simply calculate the set difference:
>>> set([...
Joda-Time: what's the difference between Period, Interval and Duration?
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3 classes are needed because they represent different concepts so it is a matter of picking the appropriate one for the job rather than of relative performance. From the documentation with comments added by me in italics:
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Windows shell command to get the full path to the current directory?
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369
Use cd with no arguments if you're using the shell directly, or %cd% if you want to use it in ...
Python - How to sort a list of lists by the fourth element in each list? [duplicate]
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unsorted_list.sort(key=lambda x: x[3])
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How to get row from R data.frame
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130
x[r,]
where r is the row you're interested in. Try this, for example:
#Add your data
x <...
The difference between bracket [ ] and double bracket [[ ]] for accessing the elements of a list or
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336
The R Language Definition is handy for answering these types of questions:
http://cran.r-pro...