Detect null reference in an array
I want to detect whether or not a subrange of an array contains the null reference. Somehow like this:
public static <T> boolean containsNull
(T[] array, int fromInclusive, int toExclusive)
{
for (int i = fromInclusive; i < toExclusive; ++i)
{
if (array[i] =开发者_如何学JAVA= null) return true;
}
return false;
}
Is there a method like this in the Java library so I don't have to manually loop over the array? Maybe I have been spoiled by C++'s excellent support for algorithmically focused code, where I can just write:
#include <algorithm>
bool found_null = (std::find(array + from, array + to, 0) != array + to);
Check whether Arrays.asList(myArray).contains(null)
.
To check part of an array, check whether
Arrays.asList(myArray).subList(from, to).contains(null)
This will not create unnecessary copies of the array; both asList
and subList
create ArrayList
and RandomAccessSubList
objects that wrap the original array without copying it.
Apache commons-lang gives you ArrayUtils.contains(array, null)
For the range: ArrayUtils.contains(Arrays.copyOfRange(array, from, to), null)
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