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Java HashMap performance optimization / alternative
...d out the hashCode() method was to blame. It was only generating around 20,000 codes for 26 million distinct objects. That is an average of 1,300 objects per hash bucket = very very bad. However if I turn the two arrays into a number in base 52 I am guaranteed to get a unique hash code for every obj...
Adding div element to body or document in JavaScript
...sition:absolute;width:100%;height:100%;opacity:0.3;z-index:100;background:#000;"></div>';
instead of
document.body.innerHTML = '<div style="position:absolute;width:100%;height:100%;opacity:0.3;z-index:100;background:#000;"></div>';
Edit:-
Ideally you should use body.append...
Finding the index of an item in a list
...e index a hint. For instance, in this snippet, l.index(999_999, 999_990, 1_000_000) is roughly five orders of magnitude faster than straight l.index(999_999), because the former only has to search 10 entries, while the latter searches a million:
>>> import timeit
>>> timeit.timeit(...
Moment js date time comparison
..., isSameOrBefore, isSameOrAfter, isBetween
So instead of 2014-03-24T01:14:000, your datetime should be either:
2014-03-24T01:14:00 or 2014-03-24T01:14:00.000Z
otherwise you may receive the following deprecation warning and the condition will evaluate to false:
Deprecation warning: value ...
StringBuilder vs String concatenation in toString() in Java
...{
StringBuilder s = new StringBuilder();
for(int i=0;i<100000;i++)
s.append("*");
}
private static void slow()
{
String s = "";
for(int i=0;i<100000;i++)
s+="*";
}
}
The output is:
slow elapsed 11741 ms
fast elap...
How to remove all .svn directories from my application directories
... rm as it can accept. Thus, if you had a million files, it might run rm 1,000,000/65,000 times (if your shell could accept 65,002 arguments on the command line {65k files + 1 for rm + 1 for -fr}).
As persons have adeptly pointed out, the following also work:
find . -name .svn -exec rm -rf {} \;
f...
1114 (HY000): The table is full
...
You will also get the same error ERROR 1114 (HY000): The table '#sql-310a_8867d7f' is full
if you try to add an index to a table that is using the storage engine MEMORY.
share
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...
The performance impact of using instanceof in Java
... an instanceof, but the difference my quick test found was 10-20ms over 10,000,000 iterations. If "object" isn't an ObjT, though, catching the exception was over 3000x slower - over 31,000ms vs ~10ms for the instanceof.
– Steve
Feb 18 '12 at 0:27
...
Test if string is a guid without throwing exceptions?
...
Performance Benchmarks
Catch exception:
10,000 good: 63,668 ticks
10,000 bad: 6,435,609 ticks
Regex Pre-Screen:
10,000 good: 637,633 ticks
10,000 bad: 717,894 ticks
COM Interop CLSIDFromString
10,000 good: 126,120 ticks
10,000 bad: 23,1...
Return number of rows affected by UPDATE statements
...-----------------------------------------------
4 2011-07-01 00:00:00.000 2009-07-10 00:00:00.000
5 2011-07-01 00:00:00.000 2009-07-11 00:00:00.000
6 2011-07-01 00:00:00.000 2009-07-12 00:00:00.000
7 2011-07-01 00:00:00.000 2009-07-13 00:00:00.000
In your particular case, s...