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Modifying a subset of rows in a pandas dataframe
Assume I have a pandas DataFrame with two columns, A and B. I'd like to modify this DataFrame (or create a copy) so that B is always NaN whenever A is 0. How would I achieve that?
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How to draw vertical lines on a given plot in matplotlib?
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The standard way to add vertical lines that will cover your entire plot window without you having to specify their actual height is plt.axvline
import matplotlib.pyplot as plt
plt.axvline(x=0.22058956)
plt.axvline(x=0.33088437)
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“x not in y” or “not x in y”
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They always give the same result.
In fact, not 'ham' in 'spam and eggs' appears to be special cased to perform a single "not in" operation, rather than an "in" operation and then negating the result:
>>> import dis
>>> def notin():
'ham' not in 'spam and eggs'
&g...
Printf width specifier to maintain precision of floating-point value
...eventh = 1.0/7.0 results in the value below. Also shown are the preceding and following representable double floating point numbers.
OneSeventh before = 0.1428571428571428 214571170656199683435261249542236328125
OneSeventh = 0.1428571428571428 49212692681248881854116916656494140625
OneSeven...
How can I pad a value with leading zeros?
...o readers!
As commenters have pointed out, this solution is "clever", and as
clever solutions often are, it's memory intensive and relatively
slow. If performance is a concern for you, don't use this solution!
Potentially outdated: ECMAScript 2017 includes String.prototype.padStart and...
How do I measure request and response times at once using cURL?
... have a web service that receives data in JSON format, processes the data, and then returns the result to the requester.
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Add one row to pandas DataFrame
I understand that pandas is designed to load fully populated DataFrame but I need to create an empty DataFrame then add rows, one by one .
What is the best way to do this ?
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How to print color in console using System.out.println?
...or in console? I want to show data in colors when the processor sends data and in different colors when it receives data.
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Analyze audio using Fast Fourier Transform
...you need to calculate the square root of the sum of the square of its real and imaginary components. That is, if your coefficient is a + b*j, then its magnitude is sqrt(a^2 + b^2).
Once you have calculated the magnitude of each FFT coefficient, you need to figure out which audio frequency each FFT ...
How to get current time with jQuery
...one in javascript is tricky (you have to calculate the offset between your and the desired time zone and modify the date accordingly). So as mentioned in another answer, using moment.js sounds like a good idea. momentjs.com
– Chris
May 4 '15 at 8:38
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