Code Vectorization of gsub in R
You have plenty of alternatives for this problem


Using sapply

data$abstract &lt;- sapply(data$abstract, 
                        function(x){gsub(pattern = "no abstract available",
                        replacement = " ", x)})

Using mapply

data$abstract &lt;- mapply(gsub, pattern = "no abstract available",
                        replacement = " ", data$abstract)

Using the stringr package

library(stringr)
data$abstract &lt;- str_replace(data$abstract, "no abstract available", 
                             " ")



Also, check this this question on StackOverflow for more information, like solutions with match and the qdap package.