

Join
Details

- 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. »
Examples
open all close allScope (4)
Generalizations & Extensions (2)
Applications (2)
Augment a matrix by adding a row:
This can also be done with ArrayFlatten:
Neat Examples (2)
See Also
Catenate Union StringJoin Append Prepend PadLeft Flatten ArrayFlatten ArrayPad
Function Repository: AppendColumn PrependColumn JoinMap
Tech Notes
History
Introduced in 1988 (1.0) | Updated in 2003 (5.0) ▪ 2007 (6.0) ▪ 2014 (10.0)
Text
Wolfram Research (1988), Join, Wolfram Language function, https://reference.wolfram.com/language/ref/Join.html (updated 2014).
CMS
Wolfram Language. 1988. "Join." Wolfram Language & System Documentation Center. Wolfram Research. Last Modified 2014. https://reference.wolfram.com/language/ref/Join.html.
APA
Wolfram Language. (1988). Join. Wolfram Language & System Documentation Center. Retrieved from https://reference.wolfram.com/language/ref/Join.html
BibTeX
@misc{reference.wolfram_2025_join, author="Wolfram Research", title="{Join}", year="2014", howpublished="\url{https://reference.wolfram.com/language/ref/Join.html}", note=[Accessed: 08-August-2025]}
BibLaTeX
@online{reference.wolfram_2025_join, organization={Wolfram Research}, title={Join}, year={2014}, url={https://reference.wolfram.com/language/ref/Join.html}, note=[Accessed: 08-August-2025]}