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MySQL - SELECT WHERE field IN (subquery) - Extremely slow why?
...make queries faster,
don't do a SELECT * only select
the fields that you really need.
Make sure you have an index on relevant_field to speed up the equi-join.
Make sure to group by on the primary key.
If you are on InnoDB and you only select indexed fields (and things are not too complex) than MyS...
Determine if 2 lists have the same elements, regardless of order? [duplicate]
... helper function. Note that it will be quite slow (O(n²)) and should generally not be used outside of the esoteric case of unhashable and unsortable elements.
def equal_ignore_order(a, b):
""" Use only when elements are neither hashable nor sortable! """
unmatched = list(b)
for element...
UIPanGestureRecognizer - Only vertical or horizontal
I have a view that has a UIPanGestureRecognizer to drag the view vertically. So in the recognizer callback, I only update the y-coordinate to move it. The superview of this view, has a UIPanGestureRecognizer that will drag the view horizontally, just updating the x-coordinate.
...
multiprocessing: sharing a large read-only object between processes?
...ults from stdin, does work, writes intermediate results on stdout.
Connect all the workers as a pipeline:
process1 <source | process2 | process3 | ... | processn >result
Each process reads, does work and writes.
This is remarkably efficient since all processes are running concurrently. T...
Get number of digits with JavaScript
...
length is a property, not a method. You can't call it, hence you don't need parenthesis ():
function getlength(number) {
return number.toString().length;
}
UPDATE: As discussed in the comments, the above example won't work for float numbers. To make it working we c...
Why does modern Perl avoid UTF-8 by default?
...?????????????????????
Set your PERL_UNICODE envariable to AS. This makes all Perl scripts decode @ARGV as UTF‑8 strings, and sets the encoding of all three of stdin, stdout, and stderr to UTF‑8. Both these are global effects, not lexical ones.
At the top of your source file (program, module, l...
In a django model custom save() method, how should you identify a new object?
...
Not all models have an id attribute, i.e. a model extending another through a models.OneToOneField(OtherModel, primary_key=True). I think you need to use self.pk
– AJP
Apr 9 '13 at 10:21
...
How can I read SMS messages from the device programmatically in Android?
...ForResult(intent, 1);
}else {
List<Sms> lst = getAllSms();
}
}else {
List<Sms> lst = getAllSms();
}
Set app as default SMS app
@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
if (requestCode == 1...
F# changes to OCaml [closed]
... is derived from OCaml, but what major items are missing or added? Specifically I'm curious as to whether the resources available for learning OCaml are also useful to someone who wants to learn F#.
...
Why are C character literals ints instead of chars?
...
discussion on same subject
"More specifically the integral promotions. In K&R C it was virtually (?)
impossible to use a character value without it being promoted to int first,
so making character constant int in the first place eliminated that step.
There...