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How do I find duplicates across multiple columns?
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Duplicated id for pairs name and city:
select s.id, t.*
from [stuff] s
join (
select name, city, count(*) as qty
from [stuff]
group by name, city
having count(*) > 1
) t on s.name = t.name and s.city = t.city
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How to modify a global variable within a function in bash?
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When you use a command substitution (ie the $(...) construct), you are creating a subshell. Subshells inherit variables from their parent shells, but this only works one way - a subshell cannot modify the environment of its parent shell. Your v...
Why must a lambda expression be cast when supplied as a plain Delegate parameter
... new delegate type with an appropriate signature, but that's rarely useful and you end up with less opportunity for error checking.
If you want to make it easy to call Control.Invoke with an Action the easiest thing to do is add an extension method to Control:
public static void Invoke(this Contro...
Hidden features of Python [closed]
...ue
In case you're thinking it's doing 1 < x, which comes out as True, and then comparing True < 10, which is also True, then no, that's really not what happens (see the last example.) It's really translating into 1 < x and x < 10, and x < 10 and 10 < x * 10 and x*10 < 100, but...
Eclipse Workspaces: What for and why?
I have seen, read and thought of different ways of using workspaces (per project, per application (multi-asseted or not), per program language, per target (web-development, plugins,..), and so on) and I am still doubting what the best approach is.
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Principal component analysis in Python
...de. 13 years after its first public release, MDP has reached full maturity and no new features are planned in the future.
– Gabriel
Oct 5 '16 at 18:42
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Header files for x86 SIMD intrinsics
...d normally just include <immintrin.h>. It includes everything.
GCC and clang will stop you from using intrinsics for instructions you haven't enabled at compile time (e.g. with -march=native or -mavx2 -mbmi2 -mpopcnt -mfma -mcx16 -mtune=znver1 or whatever.)
MSVC and ICC will let you use int...
Using Pairs or 2-tuples in Java [duplicate]
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I think it would be better to declare x and y as public final and get rid of those getters.
– user168237
Nov 10 '10 at 3:35
51
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List of Big-O for PHP functions
...ght it'd be good idea to have it for reference somewhere. I've gone though and either via benchmark or code-skimming to characterize the array_* functions. I've tried to put the more interesting Big-O near the top. This list is not complete.
Note: All the Big-O where calculated assuming a hash look...
Scatterplot with too many points
...+ geom_point(alpha = 0.3)
Another convenient way to deal with this is (and probably more appropriate for the number of points you have) is hexagonal binning:
ggplot(df,aes(x=x,y=y)) + stat_binhex()
And there is also regular old rectangular binning (image omitted), which is more like your tr...