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View more than one project/solution in Visual Studio
... With multiple projects, if I have multiple main() methods, how do I select which I want to have compiled?
– 5Daydreams
Aug 11 at 16:12
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Drop data frame columns by name
...op=FALSE to keep R from converting your data frame to a vector if you only select a single column. Don't forget that data frames are lists, so list selection (one-dimensional like I did) works perfectly well and always returns a list. Or a data frame in this case, which is why I prefer to use it.
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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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Unicode character for “X” cancel / close?
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Note that you have to use a font that supports this character. I think DejaVu looks nice for that. I think Lucida Sans Unicode and Arial Unicode MS also support such unicode symbols. If you don't use a font that supports these characters on some browsers (especially old IE) al...
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...
Correct way to quit a Qt program?
...ose your application from main() you can use this code
int main(int argc, char *argv[]){
QApplication app(argc, argv);
...
if(!QSslSocket::supportsSsl()) return app.exit(0);
...
return app.exec();
}
The program will terminated if OpenSSL is not installed
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String.equals versus == [duplicate]
...ject, but it would be equally valid to replace "Hello" with new String(new char[] {'H', 'e', ...})
– parasietje
Sep 19 '13 at 9:46
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