r - return most common prefix in columns -


if columns in data frame share common prefix, how find out such common prefix?

note: prefix here means longest substring before number appears.

data set may like:

date,vix1,vix2,vix3,dosg124,dosg220

in case, want vix instead of dosg because more columns (3) have vix prefix.

you try table , which.max after removing 'suffix' part sub. here, assume suffix numeric part.

tbl <- table(sub('\\d+$', '', v1)) names(which.max(tbl)) #[1] "vix"

by using sub, match numeric part (\\d+) end of string ($) , replace ''

data

 v1 <- c('date', 'vix1', 'vix2', 'vix3', 'dosg124', 'dosg220')

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