Select rows from data.frame ending with a specific character string in R

Question

I\'m using R and I have a data.frame with nearly 2,000 entries that looks as follows:

> head(PVs,15)
     LogFreq   Word PhonCV  FreqDev
1593     140    w         


        

Answer 1

Method 1

You can use grepl with an appropraite regular expression. Consider the following:

x <- c("blank","wade","waste","rubbish","dedekind","bated")
grepl("^.+(de|te)$",x)
[1] FALSE  TRUE  TRUE FALSE FALSE FALSE

The regular expression says begin (^) with anything any number of times (.+) and then find either de or te ((de|te)) then end ($).

So for your data.frame try,

subset(PVs,grepl("^.+(de|te)$",Word))

Method 2

To avoid the regexp method you can use a substr method instead.

# substr the last two characters and test
substr(x,nchar(x)-1,nchar(x)) %in% c("de","te")
[1] FALSE  TRUE  TRUE FALSE FALSE FALSE

So try:

subset(PVs,substr(Word,nchar(Word)-1,nchar(Word)) %in% c("de","te"))