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How to validate an email address using a regular expression?
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Deleting lines from one file which are in another file
I have a file f1 :
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How can I round down a number in Javascript?
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What does .SD stand for in data.table in R
...his is your data.table:
DT = data.table(x=rep(c("a","b","c"),each=2), y=c(1,3), v=1:6)
setkey(DT, y)
DT
# x y v
# 1: a 1 1
# 2: b 1 3
# 3: c 1 5
# 4: a 3 2
# 5: b 3 4
# 6: c 3 6
Doing this may help you see what .SD is:
DT[ , .SD[ , paste(x, v, sep="", collapse="_")], by=y]
# y V1
# 1...
Upload files with HTTPWebrequest (multipart/form-data)
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How do I break out of a loop in Scala?
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Linux delete file with size 0 [duplicate]
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edited Feb 4 at 11:24
SakiiR
8122 silver badges1111 bronze badges
answered Mar 29 '11 at 16:41...
How do you downgrade rubygems?
I have rubygems 1.3.1 installed but I want to go back to 1.2.0. What's the command to downgrade rubygems?
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