Wolfram Language & System 11.0 (2016)|Legacy Documentation

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gives a sorted list of all the distinct elements that appear in any of the listi.

gives a sorted version of a list, in which all duplicated elements have been dropped.

Details and OptionsDetails and Options

  • If the listi are considered as sets, Union gives their union.
  • Union[list1,list2,] can be input in StandardForm and InputForm as list1list2. The character can be entered as EscunEsc or \[Union].
  • The listi must have the same head, but it need not be List.
  • Union[list1,,SameTest->test] applies test to each pair of elements in the listi to determine whether they should be considered the same.
Introduced in 1988
| Updated in 1996