[英]Passing string to float array?
Hi i have a string of numbers and want to put them into a float array so i can access the values.嗨,我有一串数字,想将它们放入浮点数组中,以便我可以访问这些值。
// this bit works fine, data is split into string array.
String fdata[] = data.split(",");
Float array_f[] = new Float(fdata.length);
// this is the bit which throws an error and causes my app to crash.
for (int i = 0; i < fdata.length; i++){
float y = Float.parseFloat(fdata[i]);
array_f[i] = y;
}
The error is a错误是一个
java nullpointerexception: attempt to invoke virtual method java.lang.string java.lang.split(java.lang.string) on a null object reference. java nullpointerexception:尝试在空对象引用上调用虚拟方法 java.lang.string java.lang.split(java.lang.string)。
thanks谢谢
adding to this i think i need to explain a bit more, so i provided more code to show what im trying to do.除此之外,我想我需要多解释一下,所以我提供了更多的代码来展示我想要做什么。
String data; //does this need to define the number of bytes needed then?
start_Acq.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
channel_a = String.valueOf(channel_Acq.getSelectedItem());
Thread thread = new Thread(new Runnable() {
@Override
public void run() {
try {
connection.start_acquisition(channel_a);
data = connection.start_acquisition(channel_a);
connection.stop_acquisition();
}catch (Exception e ){
e.printStackTrace();
}
}
});thread.start();
data_recived.setText(data);
String fdata[] = data.split(",");
Float array_f[] = new Float[fdata.length];
for(int i = 0; i<fdata.length; i++){
float y = Float.parseFloat(fdata[i]);
array_f[i] = y;
}
}
});
the problem with your code is the initialization, all you have to do is to use the primitive float instead of Float :您的代码的问题在于初始化,您所要做的就是使用原始 float 而不是 Float :
String data = "123,5468,1,25,36";
String fdata[] = data.split(",");
float array_f[] = new float[fdata.length];
for (int i = 0; i < fdata.length; i++){
array_f[i] = Float.parseFloat(fdata[i]);
System.out.println(array_f[i]);
}
First of all the data
is null;首先data
为空; fix it and try by this修复它并尝试这个
float y = java.lang.Float.parseFloat(fdata[i]);
Your array initialization is wrong, it should be like你的数组初始化错误,应该是这样
Float array_f[] = new Float[fdata.length];
after length you should have a semicolon not ','在长度之后你应该有一个分号而不是','
for (int i=0; i<fdata.length;i++){
EDIT Try this it will work编辑试试这个它会工作
String fdata[] = new String[]{"6.5", "8.5"}; //this bit works fine, data is split into string array.
Float array_f[] = new Float[fdata.length];
for (int i = 0; i < fdata.length; i++) { //this is the bit which throws an error and causes my app to crash.
float y = Float.parseFloat(fdata[i]);
array_f[i] = y;
}
System.out.println(Arrays.asList(array_f));
use this get string array to string then convert float使用这个获取字符串数组到字符串然后转换浮点数
for(int i=0;stringarray.length>i;i++){float_var = Float.valueOf(string_array.get(i)); float_array.add(float_var);}
then add float array然后添加浮点数组
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