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What is Node.js? [closed]
...Script) on a VM that is incredibly fast (V8). It is much faster than Ruby, Python, or Perl.
Ability to handle thousands of concurrent connections with minimal overhead on a single process.
JavaScript is perfect for event loops with first class function objects and closures. People already know how t...
Principal component analysis in Python
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Months later, here's a small class PCA, and a picture:
#!/usr/bin/env python
""" a small class for Principal Component Analysis
Usage:
p = PCA( A, fraction=0.90 )
In:
A: an array of e.g. 1000 observations x 20 variables, 1000 rows x 20 columns
fraction: use principal components that...
write a shell script to ssh to a remote machine and execute commands
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There are multiple remote linux machines, and I need to write a shell script which will execute the same set of commands in each machine. (Including some sudo operations). How can this be done using shell scripting?
You can do this with ssh, for exa...
How to deep copy a list?
...ist.
deepcopy(x, memo=None, _nil=[])
Deep copy operation on arbitrary Python objects.
See the following snippet -
>>> a = [[1, 2, 3], [4, 5, 6]]
>>> b = list(a)
>>> a
[[1, 2, 3], [4, 5, 6]]
>>> b
[[1, 2, 3], [4, 5, 6]]
>>> a[0][1] = 10
>>&g...
How does collections.defaultdict work?
I've read the examples in python docs, but still can't figure out what this method means. Can somebody help? Here are two examples from the python docs
...
Read an Excel file directly from a R script
...to have Perl installed on your system -- usually already true on MacOS and Linux, but takes an extra step on Windows, i.e. see http://strawberryperl.com/). There are various caveats, and alternatives, listed on the R wiki page.
The only reason I see not to do this directly is that you may want to e...
Iterate a list with indexes in Python
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python enumerate function will be satisfied your requirements
result = list(enumerate([1,3,7,12]))
print result
output
[(0, 1), (1, 3), (2, 7),(3,12)]
...
How can I compare two lists in python and return matches
I want to take two lists and find the values that appear in both.
19 Answers
19
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How to compile and run C/C++ in a Unix console/Mac terminal?
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This is the command that works on all Unix machines... I use it on Linux/Ubuntu, but it works in OS X as well. Type the following command in Terminal.app.
$ g++ -o lab21 iterative.cpp
-o is the letter O not zero
lab21 will be your executable file
iterative.cpp is your c++ file
After y...
Can modules have properties the same way that objects can?
With python properties, I can make it such that
6 Answers
6
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