In MySQL, what I did is:
update table set group = 1 where log(id) < 0
I wanna do same thing in R but I have no idea
What should I do?
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There is a package called [sqldf](https://cran.r-project.org/web/packages/sqldf/sqldf.pdf). Have a look at it. – Tim Biegeleisen Jun 21 '16 at 02:45
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`tab$group[log(tab$id) < 0] <- 1` or similar. – thelatemail Jun 21 '16 at 02:59
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Check this [out](http://stackoverflow.com/questions/20130417/update-function-sqldf-r-language) – Chirayu Chamoli Jun 21 '16 at 04:45
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We can use data.table in R. Convert the 'data.frame' to 'data.table' (setDT(tab)), using the logical condition in 'i', we assign (:=) 1 to 'group' variable. As this does in place, it would be much faster and efficient.
library(data.table)
setDT(tab)[log(id) <0, group := 1]
akrun
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Using sqldf: You cannot use group as the variable name so im changing to catg.
sqldf(c("update table set catg = 1 where log(id) < 0", "select * from main.xy"))
Chirayu Chamoli
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You can put `group` in double quotes or enclose it in square brackets. – G. Grothendieck Jun 22 '16 at 11:30
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