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How to select the rows with maximum values in each group with dplyr? [duplicate]
...py the count table into a new object. Then filter for the max of the group based on the first grouping characteristic. For example:
count_table <- df %>%
group_by(A, B) %>%
count() %>%
arrange(A, desc(n))
count_table %>%
group_by...
What is the purpose of Order By 1 in SQL select statement?
...RDER BY 1
...is known as an "Ordinal" - the number stands for the column based on the number of columns defined in the SELECT clause. In the query you provided, it means:
ORDER BY A.PAYMENT_DATE
It's not a recommended practice, because:
It's not obvious/explicit
If the column order changes, ...
Android Webview - Webpage should fit the device screen
I have tried the following to fit the webpage based on the device screen size.
21 Answers
...
Java `final` method: what does it promise?
...You can't override it in your derived class, therefore it will do what the base class author intended.
http://download.oracle.com/javase/tutorial/java/IandI/final.html
Worth noting is the part where it suggests that methods called from constructors should be final.
...
Linq to Entities join vs groupjoin
... input sequence, found all the matching items from the "inner" sequence
(based on a key projection on each sequence) and then yielded pairs of
matching elements. GroupJoin is similar, except that instead of
yielding pairs of elements, it yields a single result for each "outer"
item based on ...
“elseif” syntax in JavaScript
...e if you are actually omitting the optional block {...}. I was referencing based on EMCAScript and MDN..
– skube
Apr 21 '15 at 14:49
...
Query to count the number of tables I have in MySQL
...t to do a quick command line query to count the number of tables in my database. Is that possible? If so, what is the query?
...
Get index of selected option with jQuery
...mj: Then you are doing something wrong. The selectedIndex property is zero based. I checked the documentation and even tried it myself to be truly 100% sure about this.
– Guffa
Mar 26 '16 at 23:24
...
How can I efficiently select a Standard Library container in C++11?
...arch tag.
Ordering
If you need a container of items to always be sorted based on a particular comparison operation, you can use a set. Or a multi_set if you need multiple items to have the same value.
Or you can use a sorted std::vector, but you'll have to keep it sorted.
Stability
When iterat...
Storing time-series data, relational or non?
...n is never a Key (duplicate rows, which are prohibited in a Relational database, must be prevented by other means).
The Id column requires an additional Index, which obviously impedes the speed of INSERT/DELETE, and adds to the disk space used.
You can get rid of it. Please.
Elevation
Now ...