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Immutable vs Mutable types
... changing what the variable refers to. A mutable type can change that way, and it can also change "in place".
Here is the difference.
x = something # immutable type
print x
func(x)
print x # prints the same thing
x = something # mutable type
print x
func(x)
print x # might print something differe...
Real life example, when to use OUTER / CROSS APPLY in SQL
I have been looking at CROSS / OUTER APPLY with a colleague and we're struggling to find real life examples of where to use them.
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Peak detection in a 2D array
...nic measuring pressure under a dogs paw. I use Python for my data analysis and now I'm stuck trying to divide the paws into (anatomical) subregions.
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ROW_NUMBER() in MySQL
...
SELECT t0.col3
FROM table AS t0
LEFT JOIN table AS t1 ON t0.col1=t1.col1 AND t0.col2=t1.col2 AND t1.col3>t0.col3
WHERE t1.col1 IS NULL;
“Get the rows in the table for which no other row with matching col1,col2 has a higher col3.” (You will notice this and most other groupwise-maximum solu...
How can I match a string with a regex in Bash?
...is not a concern, I recommend using [[ instead of [ or test as it is safer and more powerful. See What is the difference between test, [ and [[ ? for details.
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Fastest Way to Serve a File Using PHP
...receives a file path, identifies what it is, sets the appropriate headers, and serves it just like Apache would.
8 Answers
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How would Git handle a SHA-1 collision on a blob?
This probably never happened in the real-world yet, and may never happen, but let's consider this: say you have a git repository, make a commit, and get very very unlucky: one of the blobs ends up having the same SHA-1 as another that is already in your repository. Question is, how would Git handle ...
Quicksort: Choosing the pivot
...
Choosing a random pivot minimizes the chance that you will encounter worst-case O(n2) performance (always choosing first or last would cause worst-case performance for nearly-sorted or nearly-reverse-sorted data). Choosing the middle el...
How do I declare and initialize an array in Java?
How do I declare and initialize an array in Java?
28 Answers
28
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Why doesn't Ruby support i++ or i-- (increment/decrement operators)?
The pre/post increment/decrement operator ( ++ and -- ) are pretty standard programing language syntax (for procedural and object-oriented languages, at least).
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