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How to optimize for-comprehensions and loops in Scala?
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Why is his functional algorithm still 55 times slower? It doesn't look like it should suffer from such horrible performance
– Elijah
Jun 16 '11 at 20:10
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Python: List vs Dict for look up table
...arge sets/dicts. The worst case scenario according to wiki.python.org/moin/TimeComplexity is O(n). I guess it depends on the internal hashing implementation at what point the average time diverges from O(1) and starts converging on O(n). You can help the lookup performance by compartmentalizing the ...
Convert string date to timestamp in Python
How to convert a string in the format "%d/%m/%Y" to timestamp?
14 Answers
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How do I measure execution time of a command on the Windows command line?
Is there a built-in way to measure execution time of a command on the Windows command line?
30 Answers
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Loop through an array in JavaScript
...atements
Cons
Too verbose
Imperative
Easy to have off-by-one errors (sometimes also called a fence post error)
2. Array.prototype.forEach
The ES5 specification introduced a lot of beneficial array methods, one of them, the Array.prototype.forEach and it gives us a concise way to iterate over an a...
Is it better practice to use String.format over string Concatenation in Java?
...ifying argument positions for your format tokens as well:
"Hello %1$s the time is %2$t"
This can then be localised and have the name and time tokens swapped without requiring a recompile of the executable to account for the different ordering. With argument positions you can also re-use the same ...
How to calculate the difference between two dates using PHP?
... 5.3). For up to date solution see jurka's answer below
You can use strtotime() to convert two dates to unix time and then calculate the number of seconds between them. From this it's rather easy to calculate different time periods.
$date1 = "2007-03-24";
$date2 = "2009-06-26";
$diff = abs(strto...
How do I find the duplicates in a list and create another list with them?
... not hashable, you cannot use sets/dicts and have to resort to a quadratic time solution (compare each with each). For example:
a = [[1], [2], [3], [1], [5], [3]]
no_dupes = [x for n, x in enumerate(a) if x not in a[:n]]
print no_dupes # [[1], [2], [3], [5]]
dupes = [x for n, x in enumerate(a) if...
Why start an ArrayList with an initial capacity?
...atedly reallocated as the list grows.
The larger the final list, the more time you save by avoiding the reallocations.
That said, even without pre-allocation, inserting n elements at the back of an ArrayList is guaranteed to take total O(n) time. In other words, appending an element is an amortize...
Convert timestamp to readable date/time PHP
I have a timestamp stored in a session (1299446702).
13 Answers
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