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How to sort a dataFrame in python pandas by two or more columns?
Suppose I have a dataframe with columns a , b and c , I want to sort the dataframe by column b in ascending order, and by column c in descending order, how do I do this?
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The “backspace” escape character '\b': unexpected behavior?
...mp;R , and I learned something within the first few pages, that there is a backspace escape character, \b .
5 Answers
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Circle line-segment collision detection algorithm?
I have a line from A to B and a circle positioned at C with the radius R.
27 Answers
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Do I need to explicitly call the base virtual destructor?
...I am implementing the destructor again as virtual on the inheriting class, but do I need to call the base destructor?
7 Ans...
From ND to 1D arrays
...(for an 1D iterator):
In [12]: a = np.array([[1,2,3], [4,5,6]])
In [13]: b = a.ravel()
In [14]: b
Out[14]: array([1, 2, 3, 4, 5, 6])
Note that ravel() returns a view of a when possible. So modifying b also modifies a. ravel() returns a view when the 1D elements are contiguous in memory, but wou...
Scala type programming resources
...stion , Scala's type system is Turing complete . What resources are available that enable a newcomer to take advantage of the power of type-level programming?
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Pandas DataFrame Groupby two columns and get counts
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Followed by @Andy's answer, you can do following to solve your second question:
In [56]: df.groupby(['col5','col2']).size().reset_index().groupby('col2')[[0]].max()
Out[56]:
0
col2
A 3
B 2
C 1
D 3
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What are all the common undefined behaviours that a C++ programmer should know about? [closed]
What are all the common undefined behaviours that a C++ programmer should know about?
11 Answers
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C# - Keyword usage virtual+override vs. new
What are differences between declaring a method in a base type " virtual " and then overriding it in a child type using the " override " keyword as opposed to simply using the " new " keyword when declaring the matching method in the child type?
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How do you pass a function as a parameter in C?
I want to create a function that performs a function passed by parameter on a set of data. How do you pass a function as a parameter in C?
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