# numberToLetter: Convert numbers to letters as on a telephone's keypad In phonenumber: Convert Letters to Numbers and Back as on a Telephone Keypad

## Description

Take a character vector (i.e., a telephone number) and convert it to all all possible letter combinations as on from a telephone's key pad

## Usage

 `1` ```numberToLetter(value, decreasing = FALSE, qz = 1) ```

## Arguments

 `value` An input value as a character vector with one element (a string) `decreasing` Whether to sort the results in alphabetical order or not `qz` Whether to assign q and z to zero (qz = 0) or not (any other value)

## Value

A character vector of letters and dashes based on value

## Examples

 ``` 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19``` ```# Convert a string or a vector of numeric characters numberToLetter("911") # returns "W11" "X11" "Y11" "Z11" x <- "911" numberToLetter(x) # also returns "W11" "X11" "Y11" "Z11" # Convert a number directly numberToLetter(911) # also returns "W11" "X11" "Y11" "Z11" # Convert an alphanumeric string (letters are returned as is and # non-alphanumeric characters are returned as dashes) numberToLetter("dial 911!") # returns "DIAL-W11-" "DIAL-X11-" "DIAL-Y11-" "DIAL-Z11-" # Specifying qz = 0 maps "q" and "z" to 0 instead of 7 and 9 numberToLetter("000") # returns "000" numberToLetter("000", qz = 0) # returns "QQQ" "QQZ" "QZQ" "QZZ" "ZQQ" "ZQZ" "ZZQ" "ZZZ" ```

### Example output

```[1] "W11" "X11" "Y11" "Z11"
[1] "W11" "X11" "Y11" "Z11"
[1] "W11" "X11" "Y11" "Z11"
[1] "DIAL-W11-" "DIAL-X11-" "DIAL-Y11-" "DIAL-Z11-"
[1] "000"
[1] "QQQ" "QQZ" "QZQ" "QZZ" "ZQQ" "ZQZ" "ZZQ" "ZZZ"
```

phonenumber documentation built on May 2, 2019, 1:31 p.m.