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GROUP BY to combine/concat a column [duplicate]
...Nice! To elaborate: you are using STUFF() to remove the first comma of the concatenated PageUrl string. The PageUrl string itself is created by using FOR XML PATH(), with an empty path, to concatenate the retrieved PageUrls. Pretty clever :) Some sources: STUFF(): msdn.microsoft.com/en-us/library/ms...
How do I combine two data frames?
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You can also use pd.concat, which is particularly helpful when you are joining more than two dataframes:
bigdata = pd.concat([data1, data2], ignore_index=True, sort=False)
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Most efficient way to concatenate strings?
What's the most efficient way to concatenate strings?
17 Answers
17
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SQL: deleting tables with prefix
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In the MySQL shell or through PHPMyAdmin, use the following query
SELECT CONCAT( 'DROP TABLE ', GROUP_CONCAT(table_name) , ';' )
AS statement FROM information_schema.tables
WHERE table_name LIKE 'myprefix_%';
This will generate a DROP statement which you can than copy and execute to dr...
Calendar Recurring/Repeating Events - Best Storage Method
... EM1.`event_id` = EV.`id`
RIGHT JOIN `events_meta` EM2 ON EM2.`meta_key` = CONCAT( 'repeat_interval_', EM1.`id` )
WHERE EM1.meta_key = 'repeat_start'
AND (
( CASE ( 1299132000 - EM1.`meta_value` )
WHEN 0
THEN 1
ELSE ( 1299132000 - EM1.`meta_value` )
...
How to get the difference between two arrays of objects in JavaScript
...er(comparer(b));
var onlyInB = b.filter(comparer(a));
result = onlyInA.concat(onlyInB);
console.log(result);
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How can I add an item to a IEnumerable collection?
...rovide all items of the old one, plus some of your own. You use Enumerable.Concat for that:
items = items.Concat(new[] { "foo" });
This will not change the array object (you cannot insert items into to arrays, anyway). But it will create a new object that will list all items in the array, and th...
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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Shortcuts in Objective-C to concatenate NSStrings
Are there any shortcuts to ( stringByAppendingString: ) string concatenation in Objective-C, or shortcuts for working with NSString in general?
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How to add an object to an array
...of two arrays
var x = ['a', 'b', 'c'];
var y = ['d', 'e', 'f'];
var z = x.concat(y);
// x = ['a', 'b', 'c'] (remains unchanged)
// y = ['d', 'e', 'f'] (remains unchanged)
// z = ['a', 'b', 'c', 'd', 'e', 'f']
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