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How do you delete a column by name in data.table?
...column foo from the data.table df3:
# Method 1 (and preferred as it takes 0.00s even on a 20GB data.table)
df3[,foo:=NULL]
df3[, c("foo","bar"):=NULL] # remove two columns
myVar = "foo"
df3[, (myVar):=NULL] # lookup myVar contents
# Method 2a -- A safe idiom for excluding (possibly multiple)
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BAT file: Open new cmd window and execute a command in there
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answered Jul 9 '12 at 10:44
arossaross
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How to declare a variable in MySQL?
...lize a variable using SET or SELECT statement:
SET @start = 1, @finish = 10;
or
SELECT @start := 1, @finish := 10;
SELECT * FROM places WHERE place BETWEEN @start AND @finish;
User variables can be assigned a value from a limited set of data
types: integer, decimal, floating-point, binar...
OwinStartup not firing
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edited Sep 10 '19 at 12:41
Uwe Keim
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Are C++ enums signed or unsigned?
... an input by checking that it is = your min value (assuming you started at 0 and incremented by 1)?
9 Answers
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When should I make explicit use of the `this` pointer?
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edited Jun 14 '09 at 19:50
Bastien Léonard
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Call Activity method from adapter
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307
Yes you can.
In the adapter Add a new Field :
private Context mContext;
In the adapter Cons...
How can I change the file type association of an existing file in WebStorm?
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10 Answers
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How do I get an ISO 8601 date on iOS?
It's easy enough to get the ISO 8601 date string (for example, 2004-02-12T15:19:21+00:00 ) in PHP via date('c') , but how does one get it in Objective-C (iPhone)? Is there a similarly short way to do it?
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Install gitk on Mac
...own formula: https://github.com/Homebrew/homebrew-core/commit/dfa3ccf1e7d3901e371b5140b935839ba9d8b706)
Run the following commands at the terminal:
brew update
brew install git
brew install git-gui
If you get an error indicating it could not link git, then you may need to change permissions/owne...