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Which

Which[test1, value1, test2, value2, ...]
evaluates each of the testi in turn, returning the value of the valuei corresponding to the first one that yields True.
  • If any of the testi evaluated by Which give neither True nor False, then a Which object containing these remaining elements is returned unevaluated.  »
  • You can make Which return a "default value" by taking the last testi to be True.
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