将字符串转换为浮点数在处理中发生 NaN 错误 [英] Convert string to float occurs NaN error in Processing

问题描述

我在Processing中遇到一个问题，当我将值(字符串)转换为浮点数时，第一个值是好的，但其余的都是NaN.我找不到解决这个问题的方法.我打印字符串值进行测试.这是正确的，但在我将其转换为浮点数之后.它将是 NaN.

I meet a problem in the Processing, and when i convert the value(string) into float, the first value is good, but the rests are all NaN. I could not find a way to solve this. And i print the string value for test. And it is correct, but after i convert it into float. It will be NaN.

ps:该值来自串行，我将我的 Arduino 与 Proceesing 连接起来.

ps: the value is from the serial, i connected my Arduino with Proceesing.

以下是代码的一部分

while(myport.available() > 0)
  {
    myString = myport.readString(); //read the string from serial
    num = float(myString);          // convert the string into float
    print(num);                     // print the num(float), but the first 
                                    // value is good, rests are all `NaN` .
    //print(myString);              // print string, all the values are good
    print(' ');
    if(myString != null)
    {
       //num = float(myString);
       storeData(myString);
       //println(myString);
       //print(data[i - 1]);
       //println(' ');
       delay(1000);
    }
   }

以下是结果

以下是arduino代码

  sum = sqrt(Xg*Xg + Yg*Yg + Zg * Zg);
  sum *= 10;  
  sum = (map(sum, 0, 1024, 0, 5000)/10.0);
  Serial.println(sum);
  delay(100);

推荐答案

我发现我的问题出在 Arduino 代码中，所以我改变了从 Arduino 发送数据的方式.我使用 println() 发送数据.这就是导致 NaN 的重点.我在谷歌上搜索，然后我测试了不同的方法来改变发送方式，直到我找到这个链接:http://www.varesano.net/blog/fabio/sending-float-variables-over-serial-without-loss-precision-arduino 和处理

I find my problem is inside the Arduino code, so i changed the way to send the data from Arduino. I used the println() to send the data. And that's the point lead to NaN. I serached on google, and then i tested different ways to change the way to send until i finded this link:http://www.varesano.net/blog/fabio/sending-float-variables-over-serial-without-loss-precision-arduino-and-processing

感谢 fabio 的博客，他的博客介绍了解决此问题的好方法.如果你有同样的问题，也许你可以通过这个解决.

And thanks fabio's blog, his blog's introudces a good way to solve this problem. If you have the same trouble, maybe you can fixed by this.

这篇关于将字符串转换为浮点数在处理中发生 NaN 错误的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！