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Difference between float and decimal data type
...mysql> insert into numbers values (100, 100);
mysql> select @a := (a/3), @b := (b/3), @a * 3, @b * 3 from numbers \G
*************************** 1. row ***************************
@a := (a/3): 33.333333333
@b := (b/3): 33.333333333333
@a + @a + @a: 99.999999999000000000000000000000
@b + @b...
Difference between `mod` and `rem` in Haskell
...
183
They're not the same when the second argument is negative:
2 `mod` (-3) == -1
2 `rem` (-3) =...
C++11 reverse range-based for-loop
...
234
Actually Boost does have such adaptor: boost::adaptors::reverse.
#include <list>
#inclu...
Iterating over dictionaries using 'for' loops
...
13 Answers
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Return two and more values from a method
...
def sumdiff(x, y)
return x+y, x-y
end
#=> nil
sumdiff(3, 4)
#=> [7, -1]
a = sumdiff(3,4)
#=> [7, -1]
a
#=> [7, -1]
a,b=sumdiff(3,4)
#=> [7, -1]
a
#=> 7
b
#=> -1
a,b,c=sumdiff(3,4)
#=> [7, -1]
a
#=> 7
b
#=> -1
c
#=> nil
...
How can I obtain an 'unbalanced' grid of ggplots?
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73
grid.arrange draws directly on the device; if you want to combine it with other grid objects you...
How to make a flat list out of list of lists?
...e the timeit module in the standard library:
$ python -mtimeit -s'l=[[1,2,3],[4,5,6], [7], [8,9]]*99' '[item for sublist in l for item in sublist]'
10000 loops, best of 3: 143 usec per loop
$ python -mtimeit -s'l=[[1,2,3],[4,5,6], [7], [8,9]]*99' 'sum(l, [])'
1000 loops, best of 3: 969 usec per loo...
When is SQLiteOpenHelper onCreate() / onUpgrade() run?
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359
SQLiteOpenHelper onCreate() and onUpgrade() callbacks are invoked when the database is actuall...
匿名过程入门：倒计时与回调 - App Inventor 2 案例教程 · App Inventor 2 中文网
...：把过程存进变量
第 2 关：给匿名过程加输入项
第 3 关：后台运行 + 回调（本篇高潮）
第 4 关：延时倒计时 3、2、1
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