CODEWITHSUNDEEP
androidarraylist
androniennn
androniennn

Reputation: 3137

How to convert ArrayList<String> to Float[]

I have to retrieve some data from a file to show it in a chart. The function that shows the chart requires he data as float[] whereas the retrieved data is in the form ArrayList<String>.

What is the easiest way to convert ArrayList<String> to float[]?

        try {
            FileInputStream fIn = context.openFileInput(fileDir+fileName);
            InputStreamReader ipsr = new InputStreamReader(fIn);
            BufferedReader b = new BufferedReader(ipsr);

            ArrayList<String> list_prix = new ArrayList<String>();
            String ligne;

            while ((ligne = b.readLine()) != null) {
                String dtVal = ligne.split(" ")[2];
                dtVal = dtVal.substring(0, dtVal.length() - 2);
                list_prix.add(dtVal);
            }

            //just here if i can convert list_prix to float[]

            fIn.close();
            ipsr.close();
        } 
        catch (Exception e) 
        {
            Log.e("blah", "Exception", e);
        }

Thank you for your help.

Upvotes: 0

Views: 3583

Answers (2)

Richard
Richard

Reputation: 2110

You can loop and use Float.parseFloat().

float [] floatValues = new float[list_prix.size()];

for (int i = 0; i < list_prix.size(); i++) {
    floatValues[i] = Float.parseFloat(list_prix.get(i));
}

Now, this assumes that every string in your ArrayList can actually be parsed into a float. If not, it could throw an exception, so you may want to do this in a try/catch block if you are not sure.

Upvotes: 2

Andrew White
Andrew White

Reputation: 53516

I think the following will do it using Guava...

Collection<Float> floats = Collections2.transform(list_prix, new Function<String, Float>() {
    public Float apply(String input) {
        return Float.parseFloat(input);
    }

});

Float[] floatArray = new Float[floats.size()];
floats.toArray(floatArray);

Upvotes: 3

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