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How can I determine the direction of a jQuery scroll event?
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Check current scrollTop vs previous scrollTop
var lastScrollTop = 0;
$(window).scroll(function(event){
var st = $(this).scrollTop();
if (st > lastScrollTop){
// downscroll code
} else {
// upscroll code
}
lastScrollT...
Get value of dynamically chosen class constant in PHP
...s to understand them, but haven't seen much in terms of performance impact vs the accepted answer. THAT is something I'm interested in knowing. Instantiating a new class seems like it'd have a bigger performance hit than simply calling a constant statically. What are your thoughts on that?
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Can you “ignore” a file in Perforce?
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community wiki
21 revs, 2 users 98%Colonel Panic
2
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What is the difference between call and apply?
...ly. I can't tell you exactly why.
See jsPerf, http://jsperf.com/test-call-vs-apply/3
[UPDATE!]
Douglas Crockford mentions briefly the difference between the two, which may help explain the performance difference... http://youtu.be/ya4UHuXNygM?t=15m52s
Apply takes an array of arguments, while C...
Why start an ArrayList with an initial capacity?
...aranteed to run in O(1).
1000000 + 1000000 = 2000000 operations
Java vs C#
Java is as above, starting at 10 and increasing each resize at 50% + 1. C# starts at 4 and increases much more aggressively, doubling at each resize. The 1000000 adds example from above for C# uses 3097084 operations.
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Set a default parameter value for a JavaScript function
...ned. Plus that way you'd get a reference error if you misspelled undefined vs. putting it in a string.
– Abe Voelker
May 21 '15 at 22:04
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How do I get the path of the current executed file in Python?
...e not so small... might be a load immediate or something even faster for 0 vs a load global for _?) Debatable whether it's cleaner or easier to read or even more clever/obscure.
– ArtOfWarfare
Dec 22 '17 at 22:19
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Purpose of Trigraph sequences in C++?
...rt (IBM's for example). Microsoft started supporting a warning (C4837) in VS2008 that must be explicitly enabled (using -Wall or something).
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What is the difference between String.slice and String.substring?
...erence between substring and slice in Firefox 22. jsperf.com/string-slice-vs-substring
– Rick
Jul 17 '13 at 21:29
4
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How many double numbers are there between 0.0 and 1.0?
...s (for any "normal" floating point representation of any base and exponent vs fraction lengths) lie between 0.0 and 1.0 (another quarter between 1.0 and infinity, and the remaining half on the negative half of the real axis). Essentially, half the values of the exponent (with a normal bias, halfway...