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Convert column classes in data.table
...i")))]
}
invisible(x)
}
The function .. makes sure we get a variable out of the scope of data.table; set_colclass will set the classes of your cols.
You can use it like this:
dt <- data.table(i=1:3,f=3:1)
set_colclass(dt, c(i="character"))
class(dt$i)
...
How to create index on JSON field in Postgres?
...side a sub-object of your JSON column, thanks to @DanielRikowski I figured out I needed to do create index idx_name on table_name ((json_column->'child_obj'->>'child_obj_field')); We first need to use -> to get the JSON object and then ->> to get the child object value as text.
...
How to sort a list of objects based on an attribute of the objects?
...,other.count)
longList = [C(random.random()) for i in xrange(1000000)] #about 6.1 secs
longList2 = longList[:]
longList.sort() #about 52 - 6.1 = 46 secs
longList2.sort(key = lambda c: c.count) #about 9 - 6.1 = 3 secs
My, very minimal, tests show the first sort is more than 10 times slower, but t...
How do you clone a Git repository into a specific folder?
...u wanted it, i.e.:
ln -sfn /opt/projectA/test/public /httpdocs/public
without moving files around. Added -fn in case someone is copying these lines (-f is force, -n avoid some often unwanted interactions with already and non-existing links).
If you just want it to work, use Option A, if someone el...
How to get folder path from file path with CMD
...from a path if you are NOT using passed in values. I was able to work this out from this thread, but in case others aren't so lucky, here is how it is done:
@echo off
setlocal enabledelayedexpansion enableextensions
set myPath=C:\Somewhere\Somewhere\SomeFile.txt
call :file_name_from_path result !m...
Why implement interface explicitly?
...
For that one, I'd I'd prefer interface ICloneable<out T> { T Clone(); T self {get;} }. Note that there is deliberately no ICloneable<T> constraint on T. While an object can generally only be safely cloned if its base can be, one may wish to derive from a base clas...
How to draw border on just one side of a linear layout?
I'm able to draw border to a linear layout, but it is getting drawn on all sides. I want to restrict it to right side only, like you do in CSS (border-right:1px solid red;).
...
How to detect the currently pressed key?
...something, you haven't answered the question properly. The OP is asking about all keys and used the Shift key as an example only. So how do you detect other keys such as A to Z, 0 to 9 etc.
– Ash
Dec 18 '09 at 10:03
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How to differentiate single click event and double click event?
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You need to use a timeout to check if there is an another click after the first click.
Here is the trick:
// Author: Jacek Becela
// Source: http://gist.github.com/399624
// License: MIT
jQuery.fn.single_double_click = function(single_click_c...
Coredata Error “data: ”
I try to pull out data from CoreData with the following code
2 Answers
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