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Ruby, Difference between exec, system and %x() or Backticks
...tem
The system method calls a system program. You have to provide the command as a string argument to this method. For example:
>> system("date")
Wed Sep 4 22:03:44 CEST 2013
=> true
The invoked program will use the current STDIN, STDOUT and STDERR objects of your Ruby program. In fact...
Type of conditional expression cannot be determined because there is no implicit conversion between
... conditional expression b ? x : y, there are three possibilities, either x and y both have a type and certain good conditions are met, only one of x and y has a type and certain good conditions are met, or a compile-time error occurs. Here, "certain good conditions" means certain conversions are pos...
How to get the first column of a pandas DataFrame as a Series?
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>>> import pandas as pd
>>> df = pd.DataFrame({'x' : [1, 2, 3, 4], 'y' : [4, 5, 6, 7]})
>>> df
x y
0 1 4
1 2 5
2 3 6
3 4 7
>>> s = df.ix[:,0]
>>> type(s)
<class 'pandas.core.series.Serie...
What is context in _.each(list, iterator, [context])?
... a low-level helper. The goal is to have your custom logic bundling a verb and two nouns, with minimal boilerplate.
Admittedly, arrow functions have eliminated a lot of the "code golf" advantages of generic pure functions, but the semantic and consistency advantages remain.
I always add "use stri...
Set Colorbar Range in matplotlib
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Using vmin and vmax forces the range for the colors. Here's an example:
import matplotlib as m
import matplotlib.pyplot as plt
import numpy as np
cdict = {
'red' : ( (0.0, 0.25, .25), (0.02, .59, .59), (1., 1., 1.)),
'green':...
Plotting time in Python with Matplotlib
I have an array of timestamps in the format (HH:MM:SS.mmmmmm) and another array of floating point numbers, each corresponding to a value in the timestamp array.
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What does `someObject.new` do in Java?
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And, as you can tell, this can be incredibly confusing. Ideally, inner classes should be implementation details of the outer class and not be exposed to the outside world.
– Eric Jablow
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Numpy index slice without losing dimension information
I'm using numpy and want to index a row without losing the dimension information.
6 Answers
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How can I strip the whitespace from Pandas DataFrame headers?
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[1 rows x 3 columns]
Note: that this returns a DataFrame object and it's shown as output on screen, but the changes are not actually set on your columns. To make the changes take place, use:
Use the inplace=True argument [docs]
df.rename(columns=lambda x: x.strip(), inplace=True)
A...
Rotating a point about another point (2D)
...onizer exactly the same, just use your point subtraction/addition routines and your vector*matrix function for rotation.
– Nils Pipenbrinck
Oct 2 '17 at 4:37
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