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Random row selection in Pandas dataframe
...like this?
import random
def some(x, n):
return x.ix[random.sample(x.index, n)]
Note: As of Pandas v0.20.0, ix has been deprecated in favour of loc for label based indexing.
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Remap values in pandas column with a dict
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map also works on an index where I couldn't figure out a way to do that with replace
– Max Ghenis
Mar 15 '19 at 16:42
1
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How to validate inputs dynamically created using ng-repeat, ng-show (angular)
...s the same name as the cell above and below it. I attempted to use the {{$index}} value to name the inputs, but despite the string literals in HTML appearing correct, it is now working.
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SQL - many-to-many table primary key
...r col1 and col2 values in the referenced tables are unique) and a separate index on (col2,col1) will catch those cases where the opposite order would execute faster. The surrogate is a waste of space.
You won't need indexes on the individual columns since the table should only ever be used to join ...
Why are joins bad when considering scalability?
...means smaller (and therefore faster) comparisons during the join operation
Indexes
Materialized/indexed views (think of this as a pre-computed join or managed de-normalization)
Computed columns. You can use this to hash or otherwise pre-compute the key columns of a join, such that what would be a co...
Pandas selecting by label sometimes return Series, sometimes returns DataFrame
In Pandas, when I select a label that only has one entry in the index I get back a Series, but when I select an entry that has more then one entry I get back a data frame.
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Why are variables “i” and “j” used for counters?
...rom mathematics: the summation notation traditionally uses i for the first index, j for the second, and so on. Example (from http://en.wikipedia.org/wiki/Summation):
It's also used that way for collections of things, like if you have a bunch of variables x1, x2, ... xn, then an arbitrary one...
How to make good reproducible pandas examples
...]:
B
A
1 5
4 6
But say what's incorrect: the A column is in the index rather than a column.
do show you've done some research (search the docs, search StackOverflow), give a summary:
The docstring for sum simply states "Compute sum of group values"
The groupby docs don't give any...
Checkout another branch when there are uncommitted changes on the current branch
...ded, removed, or altered in the work-tree as part of this process, and the index/staging-area is also untouched. (Caveat: it's safe when creating a new branch without changing the new branch's starting-point; but if you add another argument, e.g., git checkout -b newbranch different-start-point, th...
Serving static files with Sinatra
...ill serve assets in public. For the empty route, you'll want to render the index document.
require 'rubygems'
require 'sinatra'
get '/' do
File.read(File.join('public', 'index.html'))
end
Routes should return a String which become the HTTP response body. File.read opens a file, reads the file,...