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pandas GroupBy columns with NaN (missing) values
...e groupby (e.g. -1):
In [11]: df.fillna(-1)
Out[11]:
a b
0 1 4
1 2 -1
2 3 6
In [12]: df.fillna(-1).groupby('b').sum()
Out[12]:
a
b
-1 2
4 1
6 3
That said, this feels pretty awful hack... perhaps there should be an option to include NaN in groupby (see this github issue ...
How to remove element from an array in JavaScript?
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12 Answers
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MySQL: What's the difference between float and double?
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edited Jan 29 '10 at 9:12
answered Jan 29 '10 at 9:04
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How to assign from a function which returns more than one value?
...ue then functionReturningTwoValues()[[1]] or functionReturningTwoValues()[[2]] would be sufficient.)
See the cited r-help thread for more examples.
(2) with If the intent is merely to combine the multiple values subsequently and the return values are named then a simple alternative is to use with...
Real life example, when to use OUTER / CROSS APPLY in SQL
...me,
pa.name
FROM sys.procedures pr
OUTER APPLY (SELECT TOP 2 *
FROM sys.parameters pa
WHERE pa.object_id = pr.object_id
ORDER BY pr.name) pa
ORDER BY pr.name,
pa.name
2) Calling a Table Valued Function for ...
How do I loop through a list by twos? [duplicate]
I want to loop through a Python list and process 2 list items at a time. Something like this in another language:
7 Answers...
Why can't R's ifelse statements return vectors?
...st vectors, you will get longer results:
> ifelse(c(TRUE, FALSE), c(1, 2), c(3, 4))
[1] 1 4
So ifelse is intended for the specific purpose of testing a vector of booleans and returning a vector of the same length, filled with elements taken from the (vector) yes and no arguments.
It is a comm...
Why use the params keyword?
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With params you can call your method like this:
addTwoEach(1, 2, 3, 4, 5);
Without params, you can’t.
Additionally, you can call the method with an array as a parameter in both cases:
addTwoEach(new int[] { 1, 2, 3, 4, 5 });
That is, params allows you to use a shortcut when call...
javascript i++ vs ++i [duplicate]
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207
The difference between i++ and ++i is the value of the expression.
The value i++ is the value...
Printing the correct number of decimal points with cout
I have a list of float values and I want to print them with cout with 2 decimal places.
12 Answers
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