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Drop unused factor levels in a subsetted data frame
...t, so the mydf <- droplevels(mydf) solution suggested by Roman Luštrik and Tommy O'Dell below is preferable.
– Johan
May 9 '14 at 10:41
1
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How do I see all foreign keys to a table or column?
...HEMA.KEY_COLUMN_USAGE
WHERE
REFERENCED_TABLE_SCHEMA = '<database>' AND
REFERENCED_TABLE_NAME = '<table>';
For a Column:
SELECT
TABLE_NAME,COLUMN_NAME,CONSTRAINT_NAME, REFERENCED_TABLE_NAME,REFERENCED_COLUMN_NAME
FROM
INFORMATION_SCHEMA.KEY_COLUMN_USAGE
WHERE
REFERENCED_TABL...
Highlight all occurrence of a selected word?
...
In Normal mode:
:set hlsearch
Then search for a pattern with the command / in Normal mode, or <Ctrl>o followed by / in Insert mode. * in Normal mode will search for the next occurrence of the word under the cursor. The hlsearch option will highlight all of them if set. # will search for ...
What does 'super' do in Python?
...tends yours. If somebody later wanted to write a class that extended Child and a mixin, their code would not work properly.
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No visible cause for “Unexpected token ILLEGAL”
...our basic token types, it gets labelled "ILLEGAL" on most implementations, and this error is thrown.
The same error is raised if, for example, you try to run a js file with a rogue @ character, a misplaced curly brace, bracket, "smart quotes", single quotes not enclosed properly (e.g. this.run('dev1...
How to show changed file name only with git log? [duplicate]
...rs find it useful:
git diff --name-only
You can also couple this with standard commit pointers to see what has changed since a particular commit:
git diff --name-only HEAD~3
git diff --name-only develop
git diff --name-only 5890e37..ebbf4c0
This succinctly provides file names only which is gre...
JSON to pandas DataFrame
...t elevation data from a google maps API along a path specified by latitude and longitude coordinates as follows:
11 Answers...
jQuery hasClass() - check for more than one class
... ... um, but I just ran this in jsperf for Chrome 21.0.1180 and the is() method is now about 20% faster. But the hasClass() seems more readable.
– Danyal Aytekin
Sep 27 '12 at 12:27
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Set margins in a LinearLayout programmatically
...va ( not XML ) to create a LinearLayout with buttons that fill the screen, and have margins. Here is code that works without margins:
...
How to have the cp command create any necessary folders for copying a file to a destination [duplica
...
To expand upon Christian's answer, the only reliable way to do this would be to combine mkdir and cp:
mkdir -p /foo/bar && cp myfile "$_"
As an aside, when you only need to create a single directory in an existing hierar...