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Why can a function modify some arguments as perceived by the caller, but not others?
I'm trying to understand Python's approach to variable scope. In this example, why is f() able to alter the value of x , as perceived within main() , but not the value of n ?
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General suggestions for debugging in R
...r silver bullet. There are good strategies for debugging in any language, and they apply here too (e.g. read this nice article). For instance, the first thing is to reproduce the problem...if you can't do that, then you need to get more information (e.g. with logging). Once you can reproduce it, ...
When should I use @classmethod and when def method(self)?
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Your guess is correct - you understand how classmethods work.
The why is that these methods can be called both on an instance OR on the class (in both cases, the class object will be passed as the first argument):
class Dummy(object):
@classmethod
d...
initialize a numpy array
Is there way to initialize a numpy array of a shape and add to it? I will explain what I need with a list example. If I want to create a list of objects generated in a loop, I can do:
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Creating a dictionary from a csv file?
...ary from a csv file. The first column of the csv file contains unique keys and the second column contains values. Each row of the csv file represents a unique key, value pair within the dictionary. I tried to use the csv.DictReader and csv.DictWriter classes, but I could only figure out how to g...
Metadata file '.dll' could not be found
I am working on a WPF, C# 3.0 project, and I get this error:
91 Answers
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pandas GroupBy columns with NaN (missing) values
...the same placeholder hack).
However, as described in another answer, from pandas 1.1 you have better control over this behavior, NA values are now allowed in the grouper using dropna=False
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Logic to test that 3 of 4 are True
I want to return True if and only if 3 out of 4 boolean values are true.
27 Answers
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What is a “cache-friendly” code?
What is the difference between " cache unfriendly code " and the " cache friendly " code?
9 Answers
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Maven Snapshot Repository vs Release Repository
What is the difference between a Snapshot Repository and Release Repository?
5 Answers
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