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What does the “map” method do in Ruby?
I'm new to programming. Can someone explain what .map would do in:
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Method chaining - why is it a good practice, or not?
... writing code easier (especially with IntelliSense). Mind you that this is one isolated case though, and is not a general practice in my code.
The point is - in 99% cases you can probably do just as well or even better without method chaining. But there is the 1% where this is the best approach.
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How to change the foreign key referential action? (behavior)
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Old question but adding answer so that one can get help
Its two step process:
Suppose, a table1 has a foreign key with column name fk_table2_id, with constraint name fk_name and table2 is referred table with key t2 (something like below in my diagram).
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Factors in R: more than an annoyance?
One of the basic data types in R is factors. In my experience factors are basically a pain and I never use them. I always convert to characters. I feel oddly like I'm missing something.
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Elastic search, multiple indexes vs one index and types for different data sets?
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number of shards can be customized per solution you select. You may have one index with 15 primary shards, or split it to 3 indexes for 5 shards - performance perspective won't change (assuming data are distributed equally)
think about data usage. Ie. if you use kibana to visualize, it's easier to...
Python memoising/deferred lookup property decorator
Recently I've gone through an existing code base containing many classes where instance attributes reflect values stored in a database. I've refactored a lot of these attributes to have their database lookups be deferred, ie. not be initialised in the constructor but only upon first read. These attr...
What is “assert” in JavaScript?
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There is no assert in JavaScript (yet; there's talk of adding one, but it's at an early stage). Perhaps you're using some library that provides one. The usual meaning is to throw an error if the expression passed into the function is false; this is part of the general concept of asserti...
What is the difference between a thread and a fiber?
.../etc.). This means that for threads, data integrity is a big issue because one thread may be stopped in the middle of updating a chunk of data, leaving the integrity of the data in a bad or incomplete state. This also means that the operating system can take advantage of multiple CPUs and CPU cores ...
How do I check if there are duplicates in a flat list?
For example, given the list ['one', 'two', 'one'] , the algorithm should return True , whereas given ['one', 'two', 'three'] it should return False .
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How to normalize a NumPy array to within a certain range?
...ized within a range before it can be written back to a file. This can be done like so:
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