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MySQL select 10 random rows from 600K rows fast
...s 0.35s on my machine.
This is fast because the sort phase only uses the indexed ID column. You can see this behaviour in the explain:
SELECT * FROM tbl ORDER BY RAND() LIMIT 10:
SELECT * FROM tbl AS t1 JOIN (SELECT id FROM tbl ORDER BY RAND() LIMIT 10) as t2 ON t1.id=t2.id
Weighted Version: ...
Adding gif image in an ImageView in android
...r table
protected int[] act; // active color table
protected int bgIndex; // background color index
protected int bgColor; // background color
protected int lastBgColor; // previous bg color
protected int pixelAspect; // pixel aspect ratio
protected boolean lctFlag; // local ...
Rebase array keys after unsetting elements
...e but you can't use it inside a for/foreach loop because it rearranges the index every time you call it, so the index of the foreach loop doesn't point to the next element but to the element with that position on the rearranged array. You can see in you example you are deleting the value '3' and lea...
Flask raises TemplateNotFound error even though template file exists
...ems like my local flask (on Windows) can find templates inside ./Templates/index.html, but when I deploy to heroku (thought it was same Python, same library versions, including same Flask version; but heroku is Unix); and throws TemplateNotFound error; after I renamed the folder git mv Templates/ind...
How do I reverse an int array in Java?
...ta[right];
data[right] = temp;
// move the left and right index pointers in toward the center
left++;
right--;
}
}
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MySQL: Fastest way to count number of rows
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When you COUNT(*) it takes in count column indexes, so it will be the best result. Mysql with MyISAM engine actually stores row count, it doensn't count all rows each time you try to count all rows. (based on primary key's column)
Using PHP to count rows is not very ...
Iterate through object properties
... true for obj.hasOwnProperty(key)).
Object.keys(obj).forEach(function(key,index) {
// key: the name of the object key
// index: the ordinal position of the key within the object
});
This is better (and more readable) than using a for-in loop.
Its supported on these browsers:
Firefox ...
Correct way of using JQuery-Mobile/Phonegap together?
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This worked for me too but if I add <div id="test-index-page" data-role="page"> </div> to the same page before html tag closes the page doesn't load and I get errors. I want to start using both frameworks using a third js file from the point both are loaded. How d...
How to get number of entries in a Lua table?
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Sadly, it appears the __newindex function doesn't fire on nil assignments unless the index doesn't exist, so it seems you'd have to funnel entry removal through a special function.
– ergosys
Apr 26 '10 at 4:43
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How do you access command line arguments in Swift?
...e the top level constants C_ARGC and C_ARGV.
for i in 1..C_ARGC {
let index = Int(i);
let arg = String.fromCString(C_ARGV[index])
switch arg {
case "this":
println("this yo");
case "that":
println("that yo")
default:
println("dunno bro")
}
}
...