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How to select rows with one or more nulls from a pandas DataFrame without listing columns explicitly
I have a dataframe with ~300K rows and ~40 columns.
I want to find out if any rows contain null values - and put these 'null'-rows into a separate dataframe so that I could explore them easily.
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How exactly does tail recursion work?
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answered Mar 20 '13 at 9:11
Alexey FrunzeAlexey Frunze
56.8k99 gold badges6767 silver badges154154 bronze badges
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How assignment works with Python list slice?
...ete, or replace contents from a list:
Insertion:
>>> a = [1, 2, 3]
>>> a[0:0] = [-3, -2, -1, 0]
>>> a
[-3, -2, -1, 0, 1, 2, 3]
Deletion:
>>> a
[-3, -2, -1, 0, 1, 2, 3]
>>> a[2:4] = []
>>> a
[-3, -2, 1, 2, 3]
Replacement:
>>> a
[-...
Apply a function to every row of a matrix or a data frame
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You simply use the apply() function:
R> M <- matrix(1:6, nrow=3, byrow=TRUE)
R> M
[,1] [,2]
[1,] 1 2
[2,] 3 4
[3,] 5 6
R> apply(M, 1, function(x) 2*x[1]+x[2])
[1] 4 10 16
R>
This takes a matrix and applies a (silly) function to each row. You pass extr...
NameError: global name 'xrange' is not defined in Python 3
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You are trying to run a Python 2 codebase with Python 3. xrange() was renamed to range() in Python 3.
Run the game with Python 2 instead. Don't try to port it unless you know what you are doing, most likely there will be more problems beyond xrange() vs. range().
For the recor...
Version of SQLite used in Android?
...database.sqlite package-level javadoc
Using the emulators:
adb shell sqlite3 --version
UPDATE: Since SDK 29 (emulator revision 8), the adb shell command gives:
/system/bin/sh: sqlite3: inaccessible or not found
Any ideas why? Issue tracker here.
SQLite 3.28.0 (window functions!):
30-11.0-R (Re...
Searching for UUIDs in text with regex
...IDs), there are five equivalent string representations for a GUID:
"ca761232ed4211cebacd00aa0057b223"
"CA761232-ED42-11CE-BACD-00AA0057B223"
"{CA761232-ED42-11CE-BACD-00AA0057B223}"
"(CA761232-ED42-11CE-BACD-00AA0057B223)"
"{0xCA761232, 0xED42, 0x11CE, {0xBA, 0xCD, 0x00, 0xAA, 0x00, 0x57, 0...
No secret option provided to Rack::Session::Cookie warning?
I am running Rails 3.2.3, Ruby 1.9 under Fedora 17. I get this warning, when I run rails s , and how do I fix?
7 Answers
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Transpose list of lists
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355
How about
map(list, zip(*l))
--> [[1, 4, 7], [2, 5, 8], [3, 6, 9]]
For python 3.x users ...
Creating an instance of class
What's the difference between lines 1 , 2 , 3 , 4?
3 Answers
3
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