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Extracting specific columns from a data frame
...r package, if your data.frame is called df1:
library(dplyr)
df1 %>%
select(A, B, E)
This can also be written without the %>% pipe as:
select(df1, A, B, E)
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Code Wrap IntelliJ?
...o right click the gutter (the vertical bar where line number is shown) and select "Use Soft wraps" - thanks to Bajal for comment.
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SQL to determine minimum sequential days of access?
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The answer is obviously:
SELECT DISTINCT UserId
FROM UserHistory uh1
WHERE (
SELECT COUNT(*)
FROM UserHistory uh2
WHERE uh2.CreationDate
BETWEEN uh1.CreationDate AND DATEADD(d, @days, uh1.CreationDate)
) = @days O...
Mysql error 1452 - Cannot add or update a child row: a foreign key constraint fails
... have to get rid of those first.
Here's a query that can find those IDs:
SELECT DISTINCT sourcecode_id FROM
sourcecodes_tags tags LEFT JOIN sourcecodes sc ON tags.sourcecode_id=sc.id
WHERE sc.id IS NULL;
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What is the correct way to restore a deleted file from SVN?
...go to TortoiseSVN -> Merge...
Make sure "Merge a range of revisions" is selected, click Next
In the "Revision range to merge" textbox, specify the revision that removed the file
Check the "Reverse merge" checkbox, click Next
Click Merge
That is completely untested, however.
Edited by OP: Thi...
Hidden Features of Visual Studio (2005-2010)?
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Make a selection with ALT pressed - selects a square of text instead of whole lines.
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answered Sep 19 ...
Hidden Features of Xcode
...m working with a large or unfamiliar project.
To show the Favorites Bar, select the following menu option:
View > Layout > Show Favorites Bar
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edited Apr 4 '11...
AngularJS - Trigger when radio button is selected
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I just want to call some function in the controller when radio button is selected.
7 Answers
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Correct use of Multimapping in Dapper
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I just ran a test that works fine:
var sql = "select cast(1 as decimal) ProductId, 'a' ProductName, 'x' AccountOpened, cast(1 as decimal) CustomerId, 'name' CustomerName";
var item = connection.Query<ProductItem, Customer, ProductItem>(sql,
(p, c) => { p.Cu...
How do I convert an interval into a number of hours with postgres?
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Probably the easiest way is:
SELECT EXTRACT(epoch FROM my_interval)/3600
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