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data.table vs dplyr: can one do something well the other can't or does poorly?
... ## data.table syntax
left_join(DT2, DT1) ## dplyr syntax
# 2. select columns while join
DT1[DT2, .(z, i.mul)]
left_join(select(DT2, x, y, mul), select(DT1, x, y, z))
# 3. aggregate while join
DT1[DT2, .(sum(z) * i.mul), by = .EACHI]
DF1 %>% group_by(x, y) %>% summarise(z = su...
How to show SQL queries run in the Rails console?
...ecord::Relation’s to_sql method:
User.where(:id => 3).to_sql
#=> "SELECT \"users\".* FROM \"users\" WHERE \"users\".\"id\" = 3"
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How do I simulate a hover with a touch in touch enabled browsers?
...for added usefulness, add this to your CSS as well:
.hover {
-webkit-user-select: none;
-webkit-touch-callout: none;
}
To stop the browser asking you to copy/save/select the image or whatever.
Easy!
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How to copy from current position to the end of line in vi
...opy/paste between different instances, you can use the system clipboard by selecting the * register, so the commands become "*y$ for copying and "*p for pasting.
$ move-to-linebreak
$
y$ yank-to-linebreak
y,$
"*y$ select clipboard-register yank-to-linebreak
",*,y,$
"*p select clipboard-regist...
Automatic Preferred Max Layout Width is not available on iOS versions prior to 8.0
... my steps below.
In xCode's Issue Navigator right click on the error and select "Reveal In Log". (Note: @Sam suggests below, look in xCode's report navigator. Also @Rivera notes in the comments that "As of Xcode 6.1.1, clicking on the warning will automatically open and highlight the conflicting l...
Comparison of full text search engine - Lucene, Sphinx, Postgresql, MySQL?
... up the firstname field as shown.
http://localhost:8983/solr/collection1/select?q=firstname:john^2&lastname:john
As you can see, firstname field is boosted up with a score of 2.
More on SolrRelevancy
searching and indexing speed
The speed is unbelievably fast and no compromise o...
Visual Studio refuses to forget breakpoints?
...
Try this select the Breakpoints toolbar item from the Debug toolbar. This brings up the Breakpoints window. From this window, you can view all breakpoints in the application. Here, you select and clear the breakpoint by clicking the D...
Vagrant stuck connection timeout retrying
... the GUI of Virtual box to see that it was waiting for input on startup to select whether I wanted to boot directly to ubuntu or safemode etc.
To turn on the GUI you have to put this in your vagrant config Vagrantfile:
config.vm.provider :virtualbox do |vb|
vb.gui = true
end
...
Get query from java.sql.PreparedStatement [duplicate]
...ut from above code.
Before : com.mysql.jdbc.JDBC4PreparedStatement@fa9cf: SELECT * FROM test WHERE blah1=** NOT SPECIFIED ** and blah2=** NOT SPECIFIED **
After : com.mysql.jdbc.JDBC4PreparedStatement@fa9cf: SELECT * FROM test WHERE blah1='Hello' and blah2='World'
...
How to enable C++11/C++0x support in Eclipse CDT?
...> Dialect
Put -std=c++11 into text box entitled other dialect flags or select ISO C++11 from the Language standard drop down.
For CMake project
Generate eclipse project files (inside your project)
mkdir build
cd build
cmake -G"Eclipse CDT4 - Unix Makefiles" -D CMAKE_BUILD_TYPE=Debug ..
Then...