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Append an object to a list in R in amortized constant time, O(1)?
...oldlist, list(someobj))
In general, R types can make it hard to have one and just one idiom for all types and uses.
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Cartesian product of multiple arrays in JavaScript
...the newly added flatMap.
Special thanks to ECMAScript 2019 for adding flat and flatMap to the language!
Example
This is the exact example from your question:
let output = cartesian([1,2],[10,20],[100,200,300]);
Output
This is the output of that command:
[ [ 1, 10, 100 ],
[ 1, 10, 200 ],
[ 1, 10...
What is the difference between a port and a socket?
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Summary
A TCP socket is an endpoint instance defined by an IP address and a port in the context of either a particular TCP connection or the listening state.
A port is a virtualisation identifier defining a service endpoint (as distinct from a service instance endpoint aka session identifier)...
how to use “AND”, “OR” for RewriteCond on Apache?
Is this how to use AND, OR for RewriteCond on Apache?
3 Answers
3
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How to add a progress bar to a shell script?
When scripting in bash or any other shell in *NIX, while running a command that will take more than a few seconds, a progress bar is needed.
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Convert JavaScript string in dot notation into an object reference
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It is of course generally fine to do this if your use case is small and you will not run into performance issues, AND you won't need to build upon your abstraction to make it more complicated later. In fact, if this will reduce code complexity and keep things simple, you should probably go ah...
Why do we need tuples in Python (or any immutable data type)?
I've read several python tutorials (Dive Into Python, for one), and the language reference on Python.org - I don't see why the language needs tuples.
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bool operator ++ and --
... supports ++ (increment) for bool, but not -- (decrement). It this just a random decision, or there is some reason behind this?
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Binary search (bisection) in Python
Is there a library function that performs binary search on a list/tuple and return the position of the item if found and 'False' (-1, None, etc.) if not?
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Fastest way to replace NAs in a large data.table
... data.table , with many missing values scattered throughout its ~200k rows and 200 columns. I would like to re code those NA values to zeros as efficiently as possible.
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