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Linear Regression and group by in R
...regression coefficient r^2:
## make fake data
library(data.table)
set.seed(1)
dat <- data.table(x=runif(100), y=runif(100), grp=rep(1:2,50))
##calculate the regression coefficient r^2
dat[,summary(lm(y~x))$r.squared,by=grp]
grp V1
1: 1 0.01465726
2: 2 ...
Red black tree over avl tree
AVL and Red black trees are both self-balancing except Red and black color in the nodes. What's the main reason for choosing Red black trees instead of AVL trees? What are the applications of Red black trees?
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How to check if a float value is a whole number
I am trying to find the largest cube root that is a whole number, that is less than 12,000.
13 Answers
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Make the current Git branch a master branch
...kout better_branch
git merge --strategy=ours master # keep the content of this branch, but record a merge
git checkout master
git merge better_branch # fast-forward master up to the merge
If you want your history to be a little clearer, I'd recommend adding some information to the m...
How can I tell if my server is serving GZipped content?
I have a webapp on a NGinx server. I set gzip on in the conf file and now I'm trying to see if it works. YSlow says it's not, but 5 out of 6 websites that do the test say it is. How can I get a definite answer on this and why is there a difference in the results?
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How do I flush the cin buffer?
How do I clear the cin buffer in C++?
13 Answers
13
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Errors: “INSERT EXEC statement cannot be nested.” and “Cannot use the ROLLBACK statement within an I
...g call, both of which are terrible solutions:
create a temp table
openrowset your stored procedure data into it
EXAMPLE:
INSERT INTO #YOUR_TEMP_TABLE
SELECT * FROM OPENROWSET ('SQLOLEDB','Server=(local);TRUSTED_CONNECTION=YES;','set fmtonly off EXEC [ServerName].dbo.[StoredProcedureName] 1,2,3'...
How to update a pull request from forked repo?
...
I did it using below steps:
git reset --hard <commit key of the pull request>
Did my changes in code I wanted to do
git add
git commit --amend
git push -f origin <name of the remote branch of pull request>
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How can I declare optional function parameters in Javascript? [duplicate]
...fault).
With ES5:
function myFunc(a,b) {
b = b || 0;
// b will be set either to b or to 0.
}
This works as long as all values you explicitly pass in are truthy.
Values that are not truthy as per MiniGod's comment: null, undefined, 0, false, ''
It's pretty common to see JavaScript librari...
How do you create a Distinct query in HQL
...ther by using the "distinct" keyword or some other method. I am not sure if distinct is a valid keywork for HQL, but I am looking for the HQL equivalent of the SQL keyword "distinct".
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