BUILT-IN MATHEMATICA SYMBOL

Union

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

.

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

Union can be input in StandardForm and InputForm as . The character can be entered as Esc un Esc or \[Union].

Union[list₁, ..., SameTest->test] applies test to each pair of elements in the to determine whether they should be considered the same.

Give a sorted list of distinct elements:

Give a sorted list of distinct elements from all the lists:

Enter using Esc un Esc:

Give a sorted list of distinct elements:

Out[1]=

Give a sorted list of distinct elements from all the lists:

Out[1]=

Enter using Esc un Esc:

Out[1]=

Give a list of the distinct lists:

Union works with any head, not just List:

Use equivalence classes based on absolute value:

Use equivalence classes based on Floor:

Use Total of list elements:

Use equality of last and first elements:

Find divisors that occur in any of 10, 12, and 20:

Find all the triples of bits that occur in the binary decomposition of 10!:

Find the distinct elements in the iteration:

Find what options are used by a list of functions:

Split on the sorted set gives lists of the same elements:

The union is equivalent to the first elements of these lists:

Tally gets the count of identical elements and returns them in the original order:

The union is the sorted list of the elements returned by Tally:

For large sets Union may be slow with SameTest since it requires all pairwise comparisons:

When equivalence class representatives can be found, it may be faster to use Union on these:

The results are the same except for the choice of representative: