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We all remember this, right?

What a nightmare was to type a short message on these keypads. So, image writing Hello on this keypad, you had to press: 4433555555666 to get the letters “hello”.

44 = h
33 = e
555 = l
555 = l
666 = o

So creating converter would be great to troll on your friends By using this useless function, you can now convert text into numbers.

```SMSconverter <- function(tt){
st <- NULL
tti <- unlist(strsplit(paste0(tt, " "), ""))
# check if input string are letters
if (!grepl("[^A-Za-z]", tti) == TRUE){
for (i in 1:nchar(tt)){
lt <- substr(tt,i,i)
if (lt != " "){
rn <- substr(rownames(which(mm == lt, arr.ind = T)),2,2)
rep <- which(mm == lt, arr.ind = T)
st <- c(st, replicate(rep, rn))
} else { st <- c(st, "0") }
}
print(paste0(st, collapse = ""))
}

# check if input string are numbers
if(!grepl("\\D", tti) == TRUE){
tti <- unlist(strsplit(paste0(tt, ""), ""))
st <- NULL
tti <- unlist(strsplit(as.character(tt), ""))
tmp <- rle(tti)
for (i in 1:length(tmp\$lengths)){
rpt <- tmp\$lengths[i]
row_cnt <- tmp\$values[i]
lt <- mm[as.integer(row_cnt)-1,rpt]
st <- c(st, lt)
}
print(paste(st, collapse=""))
}
}
```

You can run the function as:

```SMSconverter("text")
```

and it will output you the sequence of numbers, corresponding to the text: 833998.

The function is created to convert the text to numbers and numbers to text. Yet, the nondeterministic nature of numbers prevents correct conversion in the latter case.

Let me give you an example, with my name “tomaz”. The corresponding number conversion is 8666629999.

8 = t
6666 = can be: 6, 666 or 66, 66 or 666, 6 with solutions: m,o or nn or o,m
2 = a
9999 = z

So solutions can be tmoaz, tnnaz or tomaz. Well, one might need to use also the spell checker. Anyways, the conversion fails when there are multiple letters from the same key.

As always, complete code with helper datasets is available on Github in  Useless_R_function repository. The sample file in this repository is here (filename: Convert_text_to_number.R) Check the repository for future updates.

Happy R-coding and stay healthy!