R: remove single characters from string
This splits the string and filters the substrings by length, no regex:

string &lt;- "blabla a test this that b á"
paste(Filter(function(x) nchar(x) &gt; 1,
             unlist(strsplit(string, " "))), 
      collapse=" ")
# [1] "blabla test this that"


(does not work with multiple space characters)