Wolfram Language & System 11.0 (2016)|Legacy Documentation

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concatenates lists or other expressions that share the same head.

joins the objects at level n in each of the listi.


  • The listi do not need to have head List, but must all have the same head.
  • Join works on Association objects, keeping the last value associated with any given key.
  • Join works on SparseArray objects by effectively concatenating the corresponding ordinary lists. »
  • Join[list1,list2,,n] handles ragged arrays by effectively concatenating all successive elements at level n in each of the listi. »
Introduced in 1988
| Updated in 2014