Import text file to R and change it's format

Question

I have a data in text file. The example of the text file looks like this:

"vLatitude ='23.8145833';       
vLongitude ='90.4043056';
vcontents ='LRP: LRPS</br>Start of Road From the End of Banani Rail Crossing Over Pass</br>Division:Gazipur</br>Sub-Division:Tongi';
                
vLocations = new Array(vcontents, vLatitude, vLongitude);   
locations.push(vLocations);"

Can I change it to like this in R?

eg.

  latitute  longtitude  contents
23.8145833  90.4043056  LRP: LRPS Start...Tongi

score 0 · Accepted Answer · answered Sep 12 '20 at 22:07

Solution 1

That looks a lot like javascript code. Execute the javascript (using a web browser) and save the result to JSON, then open the file with R with jsonlite.

With your example, create this file and save it as my_page.html:

<html>
<header>
<script>

// Initialize locations to be able to push more values in it
// probably not required with your full code
var locations = [];

vLatitude ='23.8145833';       
vLongitude ='90.4043056';
vcontents ='LRP: LRPS</br>Start of Road From the End of Banani Rail Crossing Over Pass</br>Division:Gazipur</br>Sub-Division:Tongi';
                
vLocations = new Array(vcontents, vLatitude, vLongitude);   
locations.push(vLocations);

// convert locations to json
var jsonData = JSON.stringify(locations);

// actually write the json to file
function download(content, fileName, contentType) {
    var a = document.createElement("a");
    var file = new Blob([content], {type: contentType});
    a.href = URL.createObjectURL(file);
    a.download = fileName;
    a.click();
}
download(jsonData, 'export_json.txt', 'text/plain');


</script>
</header>
<body>
Download should start automatically. You can look at the web console for errors.
</body>
</html>

When you open it with your web browser it should "download" a file, that you can open with R:

jsonlite::read_json("export_json.txt",simplifyVector = TRUE)

One problem is that the javascript code is created an array without names. So the names are not exported. I don't see how you could make javascript export it.

Solution 2

Instead of relying on a browser to execute the javascript code, you could do it directly in R with a javascript engine. It should give you the same result, but makes communication between the two easier.

Solution 3

If the file really looks like that all along, you might be able to remove the javascript lines that organize the arrays, and only keep the lines that define variables. In R, the symbols = and ; are technically valid, it's not too hard to rewrite the javascript into R code. Note this solution could be very fragile depending on what else is in your javascript code!

js_script <- "var locations = [];

vLatitude ='23.8145833';       
vLongitude ='90.4043056';
vcontents ='LRP: LRPS</br>Start of Road From the End of Banani Rail Crossing Over Pass</br>Division:Gazipur</br>Sub-Division:Tongi';
                
vLocations = new Array(vcontents, vLatitude, vLongitude);   
locations.push(vLocations);

// convert locations to json
var jsonData = JSON.stringify(locations);" %>%
  str_split(pattern = "\n", simplify=TRUE) %>%
  as.character() %>%
  str_trim()


# Find the lines that look like defining variables
js_script <- js_script[str_detect(js_script, pattern = "^\\w+ ?= ?'.*' ?;$")]

# make it into an R expression
r_code <- str_remove(js_script, ";$") %>%
  paste(collapse = ",")

r_code <- paste0("c(", r_code, ")")

# Execute
eval(str2expression(r_code))

Import text file to R and change it's format

1 Answers1

Solution 1

Solution 2

Solution 3