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How to select the rows with maximum values in each group with dplyr? [duplicate]
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For me, it helped to count the number of values per group. Copy 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() %>%
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How can I get around MySQL Errcode 13 with SELECT INTO OUTFILE?
I am trying to dump the contents of a table to a csv file using a MySQL SELECT INTO OUTFILE statement. If I do:
13 Answers...
Find document with array that contains a specific value
...nd that such solutions work so simply without needing JOINs and additional tables makes me wonder why I haven't started on Mongo sooner. But that's not to say either DBMS is superior over the other - it depends on your use case.
– Irvin Lim
Jun 18 '15 at 14:37
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A std::map that keep track of the order of insertion?
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You might combine a std::vector with a std::tr1::unordered_map (a hash table). Here's a link to Boost's documentation for unordered_map. You can use the vector to keep track of the insertion order and the hash table to do the frequent lookups. If you're doing hundreds of thousands of lookups,...
How do you perform a left outer join using linq extension methods
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For a (left outer) join of a table Bar with a table Foo on Foo.Foo_Id = Bar.Foo_Id in lambda notation:
var qry = Foo.GroupJoin(
Bar,
foo => foo.Foo_Id,
bar => bar.Foo_Id,
(x,y) => new { Foo = x, Bars = y...
Entity Framework Refresh context?
...ntities based on views from my Database and when I made an update over one table Entity that has navigation properties to views, the entity is update but the view don't refresh accord the new updates...just want to get again from the Db the data.
Thanks!
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Finding most changed files in Git
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A5: TYPE >> =IF(D2=TRUE,MID(A2,C2+1,18),"")
create pivot table
values: Type
Filter: isFilename = true
Rows : Type
Sub : FileName
click [Count Of TYPE] -> Sort -> Sort Largest To Smallest
shar...
Relational Database Design Patterns? [closed]
...elationships using a foreign key.
Many-to-Many relationships with a bridge table.
Optional one-to-one relationships managed with NULLs in the FK column.
Star-Schema: Dimension and Fact, OLAP design.
Fully normalized OLTP design.
Multiple indexed search columns in a dimension.
"Lookup table" that con...
How to check if a function exists on a SQL database
...s for this type argument, particularly:
FN : Scalar function
IF : Inline table-valued function
TF : Table-valued-function
FS : Assembly (CLR) scalar-function
FT : Assembly (CLR) table-valued function
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Default height for section header in UITableView
I want to set the height of the first header in my UITableView. For the other headers I want them to remain the default height. What value/constant can I put in place of "someDefaultHeight" in the code below?
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