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Remove duplicated rows using dplyr
...plyr now contains the distinct function for this purpose.
Original answer below:
library(dplyr)
set.seed(123)
df <- data.frame(
x = sample(0:1, 10, replace = T),
y = sample(0:1, 10, replace = T),
z = 1:10
)
One approach would be to group, and then only keep the first row:
df %>% g...
How to pass macro definition from “make” command line arguments (-D) to C source code?
... to a "makefile" using the option :
-Dname=value. The definition is accessible inside the makefile.
6 Answers
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What's the difference between tilde(~) and caret(^) in package.json?
After I upgraded to latest stable node and npm , I tried npm install moment --save . It saves the entry in the package.json with the caret ^ prefix. Previously, it was a tilde ~ prefix.
...
What's the difference between JPA and Hibernate? [closed]
I understand that JPA 2 is a specification and Hibernate is a tool for ORM. Also, I understand that Hibernate has more features than JPA 2. But from a practical point of view, what really is the difference?
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Merge two Git repositories without breaking file history
I need to merge two Git repositories into a brand new, third repository. I've found many descriptions of how to do this using a subtree merge (for example Jakub Narębski's answer on How do you merge two Git repositories? ) and following those instructions mostly works, except that when I commit...
'Missing recommended icon file - The bundle does not contain an app icon for iPhone / iPod Touch of
I submitted an app update, but I have received an email telling me this error has occurred:
16 Answers
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What columns generally make good indexes?
...to " What are indexes and how can I use them to optimise queries in my database? " where I am attempting to learn about indexes, what columns are good index candidates? Specifically for an MS SQL database?
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Does MySQL included with MAMP not include a config file?
...
The MySQL server of MAMP (not PRO) will be started without any my.cnf file. But you can create your own my.cnf file.
Stop servers
Create a my.cnf file in /Applications/MAMP/conf/
Add your content in to my.cnf
Save my.cnf
Start servers
You do not have to put a c...
Creating C macro with ## and __LINE__ (token concatenation with positioning macro)
I want to create a C macro that creates a function with a name based
on the line number.
I thought I could do something like (the real function would have statements within the braces):
...
Init method in Spring Controller (annotation version)
...
You can use
@PostConstruct
public void init() {
// ...
}
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