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Dynamically select data frame columns using $ and a character value
...e that must first be evaluated in the second argument. You may only pass a string which is never evaluated.
Instead use [ (or [[ if you want to extract only a single column as a vector).
For example,
var <- "mpg"
#Doesn't work
mtcars$var
#These both work, but note that what they return is d...
This IP, site or mobile application is not authorized to use this API key
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They don't without some extra effort. I just figured this out after a frustrating day yesterday; there's an additional step for apps: stackoverflow.com/a/58136437/434004
– Graham Perks
Sep 27 '19 at 14:22
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Are there good reasons not to use an ORM? [closed]
...ication on any platform on which you intend to support it, a little bit of extra porting effort for some stored procedures isn't going to make a lot of difference to your TCO. For a first approximation, 98% portable is just as good as 100% portable, and far better than convoluted or poorly performi...
SQL Server: Query fast, but slow from procedure
... the quoted answer did not solve the problem for me. The query still ran really slow from a stored procedure.
I found another answer here "Parameter Sniffing", Thanks Omnibuzz. Boils down to using "local Variables" in your stored procedure queries, but read the original for more understanding, it...
Running multiple commands with xargs
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If you're including the % character somewhere in your string passed to sh -c, then this is prone to security vulnerabilities: A filename containing $(rm -rf ~)'$(rm -rf ~)' (and that's a perfectly legal substring to have within a filename on common UNIX filesystems!) will cause ...
How to drop all tables in a SQL Server database?
...y tables.
I found that code that works and does everything you try (delete all tables from your database):
DECLARE @Sql NVARCHAR(500) DECLARE @Cursor CURSOR
SET @Cursor = CURSOR FAST_FORWARD FOR
SELECT DISTINCT sql = 'ALTER TABLE [' + tc2.TABLE_SCHEMA + '].[' + tc2.TABLE_NAME + '] DROP [' + rc1.C...
Detecting endianness programmatically in a C++ program
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Is this solution really portable? What if CHAR_BIT != 8 ?
– zorgit
May 30 '15 at 20:12
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CORS - What is the motivation behind introducing preflight requests?
...change this), but in a world with CORS the preflight mechanism provides an extra 'sanity check' so that clients and servers don't break because the underlying rules of the web have changed.
Servers that are still under development, but which contain a lot of old code and for which it's not feasible/...
How can you programmatically tell an HTML SELECT to drop down (for example, due to mouseover)?
...seen this approach, and is the reference I was hoping to find. Better with extra CSS to match hidden select's size to trigger (button, img, div, etc)... 1) Ensures clickable region fills trigger 2) Menu opens directly below trigger. Note: Might also need to add a z-index to ensure the clickable regi...
Is git-svn dcommit after merging in git dangerous?
... use git merge --no-ff work -m "commit message" instead of having an extra git commit --amend step
– tekumara
Jun 14 '12 at 2:06
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