[COLLECTIONS-800] Adding partitionBalanced(List,int) method #265
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LarsBodewig
reviewed
Dec 18, 2021
| // when index hasn't crossed the threshold we don't need balancing yet | ||
| if (currentPartitionSize > 1 && threshold > 0 && index >= threshold) { | ||
| start -= (index - threshold); // adjust start as partitions before threshold have one less element | ||
| currentPartitionSize--; // currentPartitionSize is decremented as threshold is crossed |
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Newbie myself, but I wonder if that could be written more simply:
evenlyDistributedSize = ...
if (index < threshold) { // lists before threshold should contain +1
start = index * (evenlyDistributedSize + 1);
end = start + (evenlyDistributedSize + 1);
} else {
start = index * evenlyDistributedSize + threshold; // offset other starting positions by threshold
end = start + evenlyDistributedSize;
}...or similar (Note: this is untested). The if condition and subtractions look quite complicated in my opinion.
LarsBodewig
reviewed
Dec 18, 2021
| * list, partitioned in a way to balance entries across all sublists. For example, | ||
| * partitioning a list containing {@code [a, b, c, d, e]} with a partition | ||
| * size of 3 yields {@code [[a, b, c], [d, e]]} -- an outer list containing | ||
| * two inner lists of three and two elements, all in the original order. Partitioning |
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I see why you would use the example from ListUtils.partition, however this could be confusing IMO if you start comparing what method to use and see no difference so far. I would opt for a more clear example here.
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Returns consecutive sublists of a list, partitioned in a way to balance entries across all sublists. See COLLECTIONS-800 for more details.
Implementation Notes:
Partitionclass is a private static class not used by anything else I think it's ok to just use isBalanced as a boolean instead of, say, an enum or having a separate brand new private class for this new method.partition()method.forEachtest cases (I'm a fan of Spock and data driven testing).