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How to drop columns by name in a data frame
..."z","u"))]
x y
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Or, much simpler, use the select argument of the subset function : you can then use the - operator directly on a vector of column names, and you can even omit the quotes around the names !
R> subset(df, select=-c(z,u))
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2 2 3
3 3 4
4 4 ...
How do I calculate tables size in Oracle
...BLE_NAME FORMAT A32
COLUMN OBJECT_NAME FORMAT A32
COLUMN OWNER FORMAT A10
SELECT
owner,
table_name,
TRUNC(sum(bytes)/1024/1024) Meg,
ROUND( ratio_to_report( sum(bytes) ) over () * 100) Percent
FROM
(SELECT segment_name table_name, owner, bytes
FROM dba_segments
WHERE segment_type IN...
Simulating group_concat MySQL function in Microsoft SQL Server 2005?
...sy way to do this. Lots of ideas out there, though.
Best one I've found:
SELECT table_name, LEFT(column_names , LEN(column_names )-1) AS column_names
FROM information_schema.columns AS extern
CROSS APPLY
(
SELECT column_name + ','
FROM information_schema.columns AS intern
WHERE extern....
Vim: insert the same characters across multiple lines
...as the start of a text object, which is rather useful on its own, e.g. for selecting inside a tag block (it):
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Rails ActiveRecord date between
...ne day. The field is part of the standard timestamps, is created_at . The selected date is coming from a date_select .
11...
How to detect when cancel is clicked on file input?
...s not exposed to the browser." This is not true if the dialog is closed by selecting a file.
– Trevor
Dec 1 '16 at 22:24
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Allow user to select camera or gallery for image
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How to launch a single Intent to select images from either the Gallery or the Camera, or any application registered to browse the filesystem.
Rather than creating a Dialog with a list of Intent options, it is much better to use Intent.createChooser in order...
Sublime - delete all lines containing specific value
...e got stuck for several minutes when I did Ctrl+Shift+K with 200,000 lines selected.
– Przemek D
Aug 28 '17 at 11:43
I...
Convert Month Number to Month Name Function in SQL
...
A little hacky but should work:
SELECT DATENAME(month, DATEADD(month, @mydate-1, CAST('2008-01-01' AS datetime)))
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Select tableview row programmatically
How do I programmatically select a UITableView row so that
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