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How do I convert a Ruby class name to a underscore-delimited symbol?
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how to do the reverse?
– user1406062
May 26 '13 at 8:39
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show 4 more comments
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Filtering a list based on a list of booleans
...rue, False, True, False]
>>> %timeit list(compress(list_a, fil))
100000 loops, best of 3: 2.58 us per loop
>>> %timeit [i for (i, v) in zip(list_a, fil) if v] #winner
100000 loops, best of 3: 1.98 us per loop
>>> list_a = [1, 2, 4, 6]*100
>>> fil = [True, False,...
What is the difference between JavaConverters and JavaConversions in Scala?
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EDIT: Java Conversions got @deprecated in Scala 2.13.0. Use scala.jdk.CollectionConverters instead.
JavaConversions provide a series of implicit methods that convert between a Java collection and the closest corresponding Scala collection, and vice versa. This is done by creat...
boost::flat_map and its performance compared to map and unordered_map
...e measurer itself.
u64 g_accuracy;
static u64 const errormeasure = ~((u64)0);
#ifdef _MSC_VER
#pragma intrinsic(__rdtsc)
inline u64 GetRDTSC()
{
int a[4];
__cpuid(a, 0x80000000); // flush OOO instruction pipeline
return __rdtsc();
}
inline void WarmupRDTSC()
{
int a[4];
__cpu...
Sql Server equivalent of a COUNTIF aggregate function
... a CASE statement, like this:
SELECT SUM(CASE WHEN myColumn=1 THEN 1 ELSE 0 END)
FROM AD_CurrentView
Note: in my own test NULLs were not an issue, though this can be environment dependent. You could handle nulls such as:
SELECT SUM(CASE WHEN ISNULL(myColumn,0)=1 THEN 1 ELSE 0 END)
FROM AD_Curren...
Select distinct values from a table field
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206
Say your model is 'Shop'
class Shop(models.Model):
street = models.CharField(max_length=15...
Heroku error: “Permission denied (public key)”
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edited Jul 15 '14 at 19:05
ElGavilan
5,42688 gold badges2323 silver badges3535 bronze badges
answered ...
When do I use fabs and when is it sufficient to use std::abs?
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answered Jun 25 '10 at 13:06
Mike SeymourMike Seymour
230k2424 gold badges396396 silver badges602602 bronze badges
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Execute AsyncTask several times
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edited Jun 20 at 9:12
Community♦
111 silver badge
answered Jun 16 '11 at 14:49
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Split comma-separated strings in a column into separate rows
...ckage (see code below).
The sample data given by the OP consists only of 20 rows. To create larger data frames, these 20 rows are simply repeated 1, 10, 100, 1000, 10000, and 100000 times which give problem sizes of up to 2 million rows.
Benchmark results
The benchmark results show that for su...