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pandas GroupBy columns with NaN (missing) values
...n the Missing Data section of the docs:
NA groups in GroupBy are automatically excluded. This behavior is consistent with R, for example.
One workaround is to use a placeholder before doing the 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.fil...
Is there a ceiling equivalent of // operator in Python?
...t shy of an order of magnitude faster than forcing the float division and calling ceil(), provided you care about the speed. Which you shouldn't, unless you've proven through usage that you need to.
>>> timeit.timeit("((5 - 1) // 4) + 1", number = 100000000)
1.7249219375662506
>>>...
Renaming columns in pandas
...UMNS
Use the df.rename() function and refer the columns to be renamed. Not all the columns have to be renamed:
df = df.rename(columns={'oldName1': 'newName1', 'oldName2': 'newName2'})
# Or rename the existing DataFrame (rather than creating a copy)
df.rename(columns={'oldName1': 'newName1', 'oldNam...
Is there a TRY CATCH command in Bash
... writing a shell script and need to check that a terminal app has been installed. I want to use a TRY/CATCH command to do this unless there is a neater way.
...
What's the meaning of interface{}?
...interface that has no methods.
Since there is no implements keyword, all types implement at least zero methods, and satisfying an interface is done automatically, all types satisfy the empty interface.
That means that if you write a function that takes an interface{} value as a parameter, yo...
How to make good reproducible pandas examples
...s.
Disclaimer: Writing a good question is HARD.
The Good:
do include small* example DataFrame, either as runnable code:
In [1]: df = pd.DataFrame([[1, 2], [1, 3], [4, 6]], columns=['A', 'B'])
or make it "copy and pasteable" using pd.read_clipboard(sep='\s\s+'), you can format the text for Sta...
Check if something is (not) in a list in Python
... @nightcracker That makes no sense as A not in B is reduced to doing not B.__contains__(A) which is the same as what not A in B is reduced to which is not B.__contains__(A).
– Dan D.
May 2 '12 at 0:33
...
Why are unnamed namespaces used and what are their benefits?
...ng directive already took place.
This means you can have free functions called (for example) help that can exist in multiple translation units, and they won't clash at link time. The effect is almost identical to using the static keyword used in C which you can put in in the declaration of identif...
How to determine if one array contains all elements of another array
...
Perhaps this is easier to read:
a2.all? { |e| a1.include?(e) }
You can also use array intersection:
(a1 & a2).size == a1.size
Note that size is used here just for speed, you can also do (slower):
(a1 & a2) == a1
But I guess the first is more re...
Combining two Series into a DataFrame in pandas
...
this actually avoids copying too (as compared to the dict solution)
– Jeff
Aug 5 '13 at 16:27
...