I'm trying to initialize a StringBuilder with "". These are 2 samples, the first one doesn't work while the second one works. Can anyone explain a bit more? Is this because StingBuilder is an object?
for (StringBuilder element : sb){
element = new StringBuilder("");
} // this solution doesn't work, print sb[0] = null
for(int i=0; i<sb.length; i++){
sb[i] = new StringBuilder("");
}
I'm expecting both would work.
The for-each loop hides the iterator, so your first approach will not work. Another solution would be generating a Stream<StringBuilder> and then converting that to an array. Assuming you want an array of n StringBuilder(s) that might look something like,
StringBuilder[] sb = Stream.generate(() -> new StringBuilder()).limit(n)
.toArray(size -> new StringBuilder[size]);
Note that a forEach loop over the array indices would also work
IntStream.range(0, sb.length).forEach(i -> sb[i] = new StringBuilder());
This answer is super helpful and explains in detail about what element actually is in your first for-each loop. It's an instance of an iterator, not the actual member of the StringBuilder array sb.
Your second approach works because you are populating individual array elements sb[i] with value "".
sb? Please show a complete code example that we can copy/paste, compile, and run ourselves without any additional errors than what you are asking about. This means you need to declare all variables that you use and include validSystem.out.println()calls rather than just a comment.int[]to illustrate what you are doing rather than aStringBuilder[].