I have an array String[] and I'd like to convert to array Float[]
Consider e is a String[] supplied via HttpServletRequest::getParameterMap(). I tried:
Arrays.stream(e.getValue()).mapToDouble(Float::parseFloat).boxed().toArray(Float[]::new));
Got exception:
java.lang.ArrayStoreException: java.lang.Double
So then I tried:
Arrays.stream(e.getValue()).mapToDouble(Double::parseDouble).boxed().toArray(Float[]::new));
Same result.
Arrays.stream(e.getValue()).map(Float::valueOf).toArray(Float[]::new);
You could try this to generate a Float[] array:
Arrays.stream(e.getValue()).map(Float::valueOf).toArray(Float[]::new);
You have to handle possible NumberFormatException.
Unfortunately, there is no class FloatStream for primitive float, but since you want to get an Float[] anyway, the code above is just fine.
You are still generating a Float[] array in your second test.
For a Double[] result, use:
Arrays
.stream(e.getValue())
.mapToDouble(Double::parseDouble)
.boxed()
.toArray(Double[]::new);
For a Float[] result (no need for boxed in this case), use:
Arrays
.stream(e.getValue())
.map(Float::parseFloat)
.toArray(Float[]::new);
mapToDoublefor a DoubleStream of doubles withmapfor String input parameters for parseFloat.