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Pandas - Get first row value of a given column
.... See below for an explanation of why. Because a subtle difference in
the order of indexing makes a big difference in behavior, it is better to use single indexing assignment:
df.iloc[0, df.columns.get_loc('Btime')] = x
df.iloc[0, df.columns.get_loc('Btime')] = x (recommended):
The recommende...
How to get first element in a list of tuples?
...tually a list of sets, then there is no first element because sets have no order.
Here I've created a flat list because generally that seems more useful than creating a list of 1 element tuples. However, you can easily create a list of 1 element tuples by just replacing seq[0] with (seq[0],).
...
How to select a CRAN mirror in R
...Just Works(tm), in all cases, including on headless systems (servers, IoT, etc.). Thanks, Dirk.
– Jesse Adelman
Oct 7 '18 at 22:45
4
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How dangerous is it to access an array out of bounds?
...isk), possibly bringing down the entire system. A lot of malware (viruses, etc.) exploits buffer overruns to gain unauthorized access to the system.
(One historical example: I've heard that on some old systems with core memory, repeatedly accessing a single memory location in a tight loop could li...
What is the difference between Gemfile and Gemfile.lock in Ruby on Rails
...nning different versions on different machines could lead to broken tests, etc.) You shouldn't ever have to directly edit the lock file.
Check out Bundler's Purpose and Rationale, specifically the Checking Your Code into Version Control section.
...
Throw an error in a MySQL trigger
... columns (idUser and idGuest) that must be mutually exclusive in the table orders, but i'm fairly new to triggers and i'm finding difficulties in writing it!Thx.
– Nicola Peluchetti
Mar 12 '11 at 14:44
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MySQL/SQL: Group by date only on a Datetime column
...ed date_format
SELECT date
FROM blog
GROUP BY DATE_FORMAT(date, "%m-%y")
ORDER BY YEAR(date) DESC, MONTH(date) DESC
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How to sum array of numbers in Ruby?
.../en.wikipedia.org/wiki/MapReduce
http://en.wikipedia.org/wiki/Fold_(higher-order_function)
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What are the primary differences between Haskell and F#? [closed]
...apply code transformations more freely when it isn't bound to preserve the order of (unknown) side effects. In "encouraged purity" languages you write mostly similar code so the same optimizations would be applicable, only they might invalidate side effects (which aren't there, but the compiler can'...
A monad is just a monoid in the category of endofunctors, what's the problem?
...;) and (>>=) both provide simultaneous access to the two m values in order to compute the the single return value. The logic used to compute the return value is exactly the same. If it were not for the different shapes of the functions they parameterize (f :: a -> b versus k :: a -> m b...