# Converting byte array or String to float
**URL:** https://discourse.processing.org/t/converting-byte-array-or-string-to-float/27863
**Category:** Libraries
**Created:** [February 16, 2021, 10:51am UTC](https://discourse.processing.org/t/converting-byte-array-or-string-to-float/27863 "2021-02-16T10:51:01Z")
**Posts on this page:** 7
**Page:** 1
### Author:  [@TanviM](https://discourse.processing.org/u/TanviM)
#### Post date: [February 16, 2021, 10:51am UTC](https://discourse.processing.org/t/converting-byte-array-or-string-to-float/27863/1 "2021-02-16T10:51:01Z")
Hi,
**I have been successful in getting serial data** using this - [GitHub - p5-serial/p5.serialport: Serial Port API and Server for p5.js](https://github.com/p5-serial/p5.serialport#examples) library as either byte array or string values.
But when I tried converting string to float type using float() – I get a lot of NaN values which shouldn’t be coming since data is numerical.
Alternatively, I then tried getting data from serial port as byte array. I can’t find a way to convert this array to my original float value in P5.js.
**Any ideas on how to convert byte array to float or avoid getting NaN when converting string to float?**
Appreciate your time and help. Thanks.
I have used following methods:
1. From String to Float
```auto
let incomingData;
let dataValue;
incomingData = serial.readStringUntil('\n').trim();
dataValue = float(incomingData); //standard method in P5.js -- returns NaN values
```
I also tried parseFloat() – [JavaScript parseFloat() Function - GeeksforGeeks](https://www.geeksforgeeks.org/javascript-parsefloat-function/)
```auto
dataValue = parseFloat(incomingData);
//again returns maximum values as NaN
```
1. From Byte array to float
```auto
let incomingBytes = [];
let dataValue;
incomingBytes = serial.readBytesUntil('\n');
dataValue = dataView.getFloat64(bytebuffer);
// This javascript method is not supported by P5.js it seems
```
Picture illustrates original float values that I am trying to get from serial port.
---
### Author:  [@SNICKRS](https://discourse.processing.org/u/SNICKRS)
#### Post date: [February 16, 2021, 1:25pm UTC](https://discourse.processing.org/t/converting-byte-array-or-string-to-float/27863/2 "2021-02-16T13:25:37Z")
In processing, to turn a string into a float, you use `Float.parseFloat()`. I don’t know the variant of this in p5, but maybe you can find it.
---
### Author:  [@TanviM](https://discourse.processing.org/u/TanviM)
#### Post date: [February 17, 2021, 5:39am UTC](https://discourse.processing.org/t/converting-byte-array-or-string-to-float/27863/3 "2021-02-17T05:39:45Z")
Its float() or parseFloat(). I have tried both.
Also, if I do this conversion in serialEvent – the NaN returns are much more than when I do it in draw(). I am not sure why.
---
### Author:  [@erkosone](https://discourse.processing.org/u/erkosone)
#### Post date: [February 17, 2021, 6:36am UTC](https://discourse.processing.org/t/converting-byte-array-or-string-to-float/27863/4 "2021-02-17T06:36:37Z")
In my experience, this is the best way to get data from serial/BT\_serial port on PC…
```auto
try{
if(mmInStream.available()>0){
bytes = mmInStream.read(buffer);
String s = new String(buffer, 0, bytes);
dataStr += s;
// check if last char are nl..
if(dataStr.charAt(dataStr.length()-1) == nl){
String[] list = split(dataStr, nl);
for(String rcv_str : list){
if(rcv_str.length()>0){ // last string are void..
serialEvent(rcv_str); // call serialEvent() with parsed plc data..
}
}
dataStr = "";
}
}
}catch(Exception e){
e.printStackTrace();
}
```
And this is the event function, works perfectly 😉
```auto
void serialEvent(String str){
println("From PLC:", str);
if(str.equals(sn)){
//..
}
}
```
` char nl = '#';`
---
### Author:  [@erkosone](https://discourse.processing.org/u/erkosone)
#### Post date: [February 17, 2021, 6:40am UTC](https://discourse.processing.org/t/converting-byte-array-or-string-to-float/27863/5 "2021-02-17T06:40:23Z")
La cosa es sencilla… leer bytes en un buffer hasta recibir un char concreto, tras recibirlo hay que mirar si han llegado mas de una secuencia de datos y hacer un split() usando ese mismo char… y luego enviar los datos a la función del evento.
Esto lo he preparado para Bluetoth en processing 3.4.5 y funciona muy bien con dispositivos como Arduino o raspberry pi
---
### Author:  [@TanviM](https://discourse.processing.org/u/TanviM)
#### Post date: [February 18, 2021, 5:37am UTC](https://discourse.processing.org/t/converting-byte-array-or-string-to-float/27863/6 "2021-02-18T05:37:10Z")
This is a processing (or java based) code. I have done this on processing before. But now I have to make a switch to P5.js for running my program in a web browser.
I have tried implementing try and catch as well. Doesn’t work.
When I print the incoming string type data – everything seems to look fine. But when I convert string to float; NaN values come up that shouldn’t be there.
---
### Author:  [@TanviM](https://discourse.processing.org/u/TanviM)
#### Post date: [February 18, 2021, 7:29am UTC](https://discourse.processing.org/t/converting-byte-array-or-string-to-float/27863/7 "2021-02-18T07:29:21Z")
As seen in the last image, there were empty strings or null values coming. I just had to put a check for it before doing the conversion.
Thanks to all the commenters.
```
let incomingData; //incoming serial value is stored in this variable
let temparray = [1000]; //temporary array used in updating final array
let plot_from_here = [1000]; //final array of values to plot
function setup(){}
function draw(){}
function serialEvent() {
if(serial.available()>0){
incomingData = serial.readStringUntil('\n'); //read string until next line
if(incomingData != ""){
incomingData = trim(incomingData); //trim white spaces
arrayCopy(temparray,0, temparray,1,999); //Copy value from index 0 to index 1
temparray[0]= float(incomingData); //Update index 0 of temparray for the incoming value -- the value is converted to float from string type
plot_from_here = temparray; //update values in final array
print(plot_from_here);
}
}
}
```