格式化字符串以删除科学记数法 - Java
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Formatting a String to Remove Scientific Notation - Java
提问by GuybrushThreepwood
I have the following code which splits a string of numbers (separated by a space) and then creates an array of floats :
我有以下代码，它拆分一串数字（用空格分隔），然后创建一个浮点数组：
//Split the string and then build a float array with the values.
String[] tabOfFloatString = value.split(" ");
int length = tabOfFloatString.length;
System.out.println("Length of float string is" + length);
float[] floatsArray = new float[length];
for (int l=0; l<length; l++) {
float res = Float.parseFloat(tabOfFloatString[l]);
System.out.println("Float is " + res);
floatsArray[l]=res;
}
The problem is that some of the values in the string are formatted with scientific notation - e.g they read -3.04567E-8.
问题是字符串中的一些值是用科学记数法格式化的——例如它们读取 -3.04567E-8。
What I want to do is end up with a float which does not contain the E number.
我想要做的是最终得到一个不包含 E 数字的浮点数。
I have been reading this thread which suggests that I could use BigDecimal, however am unable to get this to work - is this the best approach or should I try something else ? How to convert a string 3.0103E-7 to 0.00000030103 in Java?
我一直在阅读这个线程，它表明我可以使用 BigDecimal，但是我无法让它工作 - 这是最好的方法还是我应该尝试其他方法？如何在 Java 中将字符串 3.0103E-7 转换为 0.00000030103？
回答by dharam
Below is your code slightly modified. As per me this works well and doesn't actually cares he order of the exponents:
下面是您的代码略有修改。在我看来，这很有效，实际上并不关心指数的顺序：
public void function() {
String value = "123456.0023 -3.04567E-8 -3.01967E-20";
String[] tabOfFloatString = value.split(" ");
int length = tabOfFloatString.length;
System.out.println("Length of float string is" + length);
float[] floatsArray = new float[length];
for (int l = 0; l < length; l++) {
String res = new BigDecimal(tabOfFloatString[l]).toPlainString();
System.out.println("Float is " + res);
floatsArray[l] = Float.parseFloat(res);
}
}
回答by Copper Copperone
Accepted answered doesn't work for me, When do
接受回答对我不起作用，什么时候做
floatsArray[l] = Float.parseFloat(res);
the Float.parseFloat(res) change non scientific anotation into scientific anotation so i had to delete it.
Float.parseFloat(res) 将非科学注释更改为科学注释，因此我不得不将其删除。
This one worked:
这个有效：
public String[] avoidScientificNotation(float[] sensorsValues)
{
int length = sensorsValues.length;
String[] valuesFormatted = new String[length];
for (int i = 0; i < length; i++)
{
String valueFormatted = new BigDecimal(Float.toString(sensorsValues[i])).toPlainString();
valuesFormatted[i] = valueFormatted;
}
return valuesFormatted;
}
回答by erickson
NumberFormat format = new DecimalFormat("0.############################################################");
System.out.println(format.format(Math.ulp(0F)));
System.out.println(format.format(1F));
回答by James Montagne
The float doesn't contain an e, that is just how it is being displayed to you. You can use DecimalFormatto change how it is displayed.
浮点数不包含e，这就是它向您显示的方式。您可以使用DecimalFormat更改它的显示方式。
java.text.DecimalFormat df = new java.text.DecimalFormat("#,###.######################################################");
System.out.println(df.format(res));
You will notice some odd looking numbers though, due to floating point.
不过，由于浮点数，您会注意到一些看起来很奇怪的数字。
