Dictionary style replace multiple items

Question

I have a large data.frame of character data that I want to convert based on what is commonly called a dictionary in other languages.

Currently I am going about it li

Answer 1

Used @Ramnath's answer above, but made it read (what to be replaced and what to be replaced with) from a file and use gsub rather than replace.

hrw <- read.csv("hgWords.txt", header=T, stringsAsFactor=FALSE, encoding="UTF-8", sep="\t") 

for (i in nrow(hrw)) 
{
document <- gsub(hrw$from[i], hrw$to[i], document, ignore.case=TRUE)
}

hgword.txt contains the following tab separated

"from"  "to"
"AA"    "0101"
"AC"    "0102"
"AG"    "0103"