R中特殊字符的grep

Question

I am searching for "1." in a matrix in R using grep function. grep("1\\.",VADeaths,value=TRUE). However, it is not showing me 41.0 in the result. Why is it so? 41.0 is one of the values in one of the columns.

Answer 1

If we convert in to character , this will become more apparent

as.character(VADeaths)
#[1] "11.7" "18.1" "26.9" "41"   "66"   "8.7"  "11.7" "20.3" "30.9" "54.3" 
#[11] "15.4" "24.3" "37"   "54.6" "71.1" "8.4"  "13.6" "19.3" "35.1" "50"  

For 41 , it is just round and there is no . there

If we need to get those elements as well

grep("1\\.|^[^.]*1$", VADeaths, value = TRUE)
#[1] "11.7" "41"   "11.7" "71.1"