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String concatenation does not work in SQLite
...p>' from location;
From SQLite documentation:
The || operator is "concatenate" - it joins together the two strings of its operands.
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C# switch statement limitations - why?
...switch (ms) : 0.00237094
total time to execute a 50000 way switch, 10000 iterations (ms) : 20.0933
approximate time per 50000 way switch (ms) : 0.00200933
Then I also did using non-adjacent case expressions:
total time to execute a 10 way switch...
How to change the CHARACTER SET (and COLLATION) throughout a database?
...8. Hope this helps!
-- Change DATABASE Default Collation
SELECT DISTINCT concat('ALTER DATABASE `', TABLE_SCHEMA, '` CHARACTER SET utf8 COLLATE utf8_unicode_ci;')
from information_schema.tables
where TABLE_SCHEMA like 'database_name';
-- Change TABLE Collation / Char Set
SELECT concat('ALTER T...
Combining two Series into a DataFrame in pandas
...
I think concat is a nice way to do this. If they are present it uses the name attributes of the Series as the columns (otherwise it simply numbers them):
In [1]: s1 = pd.Series([1, 2], index=['A', 'B'], name='s1')
In [2]: s2 = pd.S...
How to extend an existing JavaScript array with another array, without creating a new array
...ed for "JavaScript array extend" and got here, you can very well use Array.concat.
var a = [1, 2, 3];
a = a.concat([5, 4, 3]);
Concat will return a copy the new array, as thread starter didn't want. But you might not care (certainly for most kind of uses this will be fine).
There's also some n...
JOIN queries vs multiple queries
...one row from a 100,000 row table. Basically looked like:
$id = mt_rand(1, 50000);
$row = $db->fetchOne("SELECT * FROM table1 WHERE id = " . $id);
$row = $db->fetchOne("SELECT * FROM table2 WHERE other_id = " . $row['other_id']);
vs
$id = mt_rand(1, 50000);
$db->fetchOne("SELECT table1.*...
What is the purpose of “!” and “?” at the end of method names?
... Beware, this isn't always the case. For example, Ruby Array#concat docs.ruby-lang.org/en/2.0.0/Array.html#method-i-concat. Where you can get burnt badly is something like MyActiveRecordModel.column_names.concat(...). Instead you must clone it before doing the concat.
...
Combine multiple Collections into a single logical Collection?
...
With Guava, you can use Iterables.concat(Iterable<T> ...), it creates a live view of all the iterables, concatenated into one (if you change the iterables, the concatenated version also changes). Then wrap the concatenated iterable with Iterables.unmodi...
How many String objects will be created when using a plus sign?
...iteLine(result);
}
then the compiler seems to emit the code using String.Concat as @Joachim answered (+1 to him btw).
If you define them as constants, e.g.:
const String one = "1";
const String two = "2";
const String result = one + two + "34";
or as literals, as in the original question:
Str...
Update MongoDB field using value of another field
...lection.<update method>(
{},
[
{"$set": {"name": { "$concat": ["$firstName", " ", "$lastName"]}}}
]
)
MongoDB 3.4+
In 3.4+ you can use $addFields and the $out aggregation pipeline operators.
db.collection.aggregate(
[
{ "$addFields": {
"name": {...