大约有 4,000 项符合查询结果（耗时：0.0233秒） [XML]
How can I iterate over an enum?
...b = 220,
c = -1
};
static const Type All[] = { a, b, c };
}
void fun( const MyEnum::Type e )
{
std::cout << e << std::endl;
}
int main()
{
// all
for ( const auto e : MyEnum::All )
fun( e );
// some
for ( const auto e : { MyEnum::a, MyEnum::b } )
fun( e );
...
Meaning of epsilon argument of assertEquals for double values
...nal double DELTA = 1e-15;
@Test
public void testDelta(){
assertEquals(123.456, 123.456, DELTA);
}
If you're using hamcrest assertions, you can just use the standard equalTo() with two doubles (it doesn't use a delta). However if you want a delta, you can just use closeTo() (see javadoc), e.g....
SQLAlchemy IN clause
...
How about
session.query(MyUserClass).filter(MyUserClass.id.in_((123,456))).all()
edit: Without the ORM, it would be
session.execute(
select(
[MyUserTable.c.id, MyUserTable.c.name],
MyUserTable.c.id.in_((123, 456))
)
).fetchall()
select() takes two parameters...
Truncate number to two decimal places without rounding
...2.55
2.99999 => 2.99
4.27 => 4.27
15.7784514 => 15.77
123.5999 => 123.59
0.000000199 => 1.99 *
* As mentioned in the note, that's due to javascript implicit conversion into exponential for "1.99e-7"
And for some other values of n:
15.001097 => 15.0010 (n=4)
0.00...
How do I return to an older version of our code in Subversion?
...nd the right revision number.
Note down the good revision number (assuming 123 for examples below).
Update to the latest revision:
svn update
Undo all the changes between the revision you want and the latest version:
svn merge -r HEAD:123 .
svn commit "Reverted to revision 123"
(the same as Jon...
Count number of rows within each group
...count the number of rows within each group. I reguarly use the aggregate function to sum data as follows:
14 Answers
...
How to get the function name from within that function?
How can I access a function name from inside that function?
20 Answers
20
...
How can I print the contents of a hash in Perl?
...
Data::Dumper is your friend.
use Data::Dumper;
my %hash = ('abc' => 123, 'def' => [4,5,6]);
print Dumper(\%hash);
will output
$VAR1 = {
'def' => [
4,
5,
6
],
'abc' => 123
...
Parse query string into an array
...alone is note accurate, it could display for example:
$url = "somepage?id=123&lang=gr&size=300";
parse_str() would return:
Array (
[somepage?id] => 123
[lang] => gr
[size] => 300
)
It would be better to combine parse_str() with parse_url() like so:
$url = "som...
Hg: How to do a rebase like git's rebase
...e:
1. Start working on a new feature:
$ hg clone mainline-repo newfeature-123
do a few commits (M, N, O)
master A---B---C
\
newfeature-123 M---N---O
2. Pull new changes from upstream mainline:
$ hg pull
master A---B---C---D---E---F
\
newfeature-123 M---N---O
...