java Java将一串浮点数解析为一个浮点数组？
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Java parsing a string of floats to a float array?
提问by Sonoman
Is there a simple way to parse a string of floats to a float array? I'm writing an importer which needs to parse an ascii file to get some values out and I'm just wondering if there's a simpler way to do this then search for all the whitespace myself and use Float.parseFloat(s)for each whitespace-separated value.
有没有一种简单的方法可以将一串浮点数解析为一个浮点数数组？我正在编写一个需要解析 ascii 文件以获取一些值的导入器，我只是想知道是否有一种更简单的方法可以做到这一点，然后自己搜索所有空格并Float.parseFloat(s)用于每个空格分隔的值。
For example, the string is
例如，字符串是
1 0 4 0 26 110.78649609798859 39 249.34908705094128 47 303.06802752888359
1 0 4 0 26 110.78649609798859 39 249.34908705094128 47 303.06802752888359
I want to create an array of floats as:
我想创建一个浮点数组：
[1, 0, 4, 0, 26, 110.78649609798859, 39, 249.34908705094128, 47, 303.06802752888359]
[1, 0, 4, 0, 26, 110.78649609798859, 39, 249.34908705094128, 47, 303.06802752888359]
Thanks for the help!
谢谢您的帮助！
回答by Reese Moore
回答by Jason Rogers
You can do like this
你可以这样做
Split the String
拆分字符串
String[] split(String regex) Splits this string around matches of the given regular expression.
String[] split(String regex) 围绕给定正则表达式的匹配项拆分此字符串。
String[] tabOfFloatString = bigStringWithAllFloats.split(regex);
regex can be space, tab, comma whatever (advantage of regex is you can combine all you want, I use this in my xml reader "[-+.,:;]" ); then loop on that and convert to floats
正则表达式可以是空格、制表符、逗号等（正则表达式的优点是你可以组合所有你想要的，我在我的 xml 阅读器中使用它 "[-+.,:;]" ）；然后循环并转换为浮点数
for(String s : tabOfFloatString){
float res = Float.parseFloat(s);
//do whatever you want with the float
}
回答by khachik
回答by G B
If you just want an array of float, the easy way is to split the string:
如果你只想要一个浮点数组，简单的方法是拆分字符串：
String[] flostr = myString.split(" ");
float[] floats = new float[flostr.length];
and then iterate on the string array, and parse the single float values.
然后迭代字符串数组，并解析单个浮点值。
Alternatively, you could use a Scanner or a StringTokenizer, put all values into a List and create an array at the end.
或者，您可以使用 Scanner 或 StringTokenizer，将所有值放入一个 List 并在最后创建一个数组。
回答by Sean Patrick Floyd
Here's a Guavasolution, but I'm surprised at how complicated it apparently needs to be. Perhaps someone can give me a hint as how to shorten it:
这是一个番石榴解决方案，但我很惊讶它显然需要多么复杂。也许有人可以给我一个关于如何缩短它的提示：
public static float[] extractFloats(final String input){
// check for null Strings
Preconditions.checkNotNull(input);
return Floats.toArray(Lists.transform(
Lists.newArrayList(Splitter.on(Pattern.compile("\s+")).split(
input.trim())), new Function<String, Float>(){
@Override
public Float apply(final String input){
return Float.valueOf(input);
}
}));
}
Test Code:
测试代码：
String param =
"1 0 4 0 26 110.78649609798859 39 249.34908705094128 47 303.06802752888359";
float[] floats = extractFloats(param);
System.out.println(Arrays.toString(floats));
Output:
输出：
[1.0, 0.0, 4.0, 0.0, 26.0, 110.7865, 39.0, 249.34909, 47.0, 303.06802]
[1.0, 0.0, 4.0, 0.0, 26.0, 110.7865, 39.0, 249.34909, 47.0, 303.06802]
