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Why were pandas merges in python faster than data.table merges in R in 2012?
... merge in mind. Two aspects to that: i) multi column ordered keys such as (id,datetime) ii) fast prevailing join (roll=TRUE) a.k.a. last observation carried forward.
I'll need some time to confirm as it's the first I've seen of the comparison to data.table as presented.
UPDATE from data.table v1...
Maven 3 warnings about build.plugins.plugin.version
...
Add a <version> element after the <plugin> <artifactId> in your pom.xml file. Find the following text:
<plugin>
<artifactId>maven-compiler-plugin</artifactId>
Add the version tag to it:
<plugin>
<artifactId>maven-compiler-plugin</art...
Rotated elements in CSS that affect their parent's height correctly
...en HTML like this, where you want to rotate .element-to-rotate...
<div id="container">
<something class="element-to-rotate">bla bla bla</something>
</div>
... introduce two wrapper elements around the element that you want to rotate:
<div id="container">
<div...
Add and remove multiple classes in jQuery
...refer to all the paragraphs on the page but it is just an example. You can identify a specific item with an ID or another class.
– Andrea_dev
Jun 18 '19 at 13:28
add a comment...
How to avoid the “divide by zero” error in SQL?
...
In order to avoid a "Division by zero" error we have programmed it like this:
Select Case when divisor=0 then null
Else dividend / divisor
End ,,,
But here is a much nicer way of doing it:
Select dividend / NULLIF(divisor, 0) ...
Now ...
Symbolic links and synced folders in Vagrant
I want to use Vagrant to provide a common development environment to my team. The hosts are completely different:
6 Answers...
How can I clone an SQL Server database on the same server in SQL Server 2008 Express?
...licking the "Databases" branch of the SQL Server Management Studio and provide the database name while providing the source to restore. ref: stackoverflow.com/questions/10204480/…
– taynguyen
Sep 15 '15 at 13:52
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SQL Query to concatenate column values from multiple rows in Oracle
...ring aggregation techniques. A very common one is to use LISTAGG:
SELECT pid, LISTAGG(Desc, ' ') WITHIN GROUP (ORDER BY seq) AS description
FROM B GROUP BY pid;
Then join to A to pick out the pids you want.
Note: Out of the box, LISTAGG only works correctly with VARCHAR2 columns.
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How can I return to a parent activity correctly?
I have 2 activities (A and B) in my android application and I use an intent to get from activity A to activity B. The use of parent_activity is enabled:
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ListView item background via custom selector
...d finally solved it. As Romain Guy hinted to, there's another state, "android:state_selected", that you must use. Use a state drawable for the background of your list item, and use a different state drawable for listSelector of your list:
list_row_layout.xml:
<?xml version="1.0" encoding="utf-8...