LongestCommonSubsequencePositions
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LongestCommonSubsequencePositions
finds the longest contiguous subsequence of elements common to the strings, biomolecular sequences or lists s1 and s2 and returns their positions {pos1,pos2} in s1 and s2.
Details and Options

- For lists si, Take[si,posi] returns the longest common subsequence. For strings si, StringTake[si,posi] returns the longest common contiguous substring.
- If there are several common subsequences of the same length, LongestCommonSubsequencePositions returns the position of the one that appears earliest in s1.
- For strings, setting the option IgnoreCase->True makes LongestCommonSubsequencePositions treat lowercase and uppercase letters as equivalent, and returns the form of common subsequence that occurs in s1.
Examples
open allclose allBasic Examples (3)Summary of the most common use cases
Find the longest contiguous subsequence common to two strings:

https://wolfram.com/xid/0hu7haiuvifua8npojn03n-dn28de

Find the longest contiguous subsequence common to two lists:

https://wolfram.com/xid/0hu7haiuvifua8npojn03n-sv4al6

Find the longest contiguous subsequence common to two biomolecular sequences:

https://wolfram.com/xid/0hu7haiuvifua8npojn03n-iku12d

Scope (2)Survey of the scope of standard use cases
Options (1)Common values & functionality for each option
IgnoreCase (1)
By default, LongestCommonSubsequencePositions distinguishes lower and upper case:

https://wolfram.com/xid/0hu7haiuvifua8npojn03n-k7aao3


https://wolfram.com/xid/0hu7haiuvifua8npojn03n-y7blo6

Applications (1)Sample problems that can be solved with this function
Properties & Relations (1)Properties of the function, and connections to other functions

https://wolfram.com/xid/0hu7haiuvifua8npojn03n-9qwao7
Find the positions of the longest common sequence of characters:

https://wolfram.com/xid/0hu7haiuvifua8npojn03n-h0r0ay

The corresponding strings coincide:

https://wolfram.com/xid/0hu7haiuvifua8npojn03n-c49aaf

LongestCommonSubsequence returns those strings joined:

https://wolfram.com/xid/0hu7haiuvifua8npojn03n-0srin2

Wolfram Research (2015), LongestCommonSubsequencePositions, Wolfram Language function, https://reference.wolfram.com/language/ref/LongestCommonSubsequencePositions.html.
Text
Wolfram Research (2015), LongestCommonSubsequencePositions, Wolfram Language function, https://reference.wolfram.com/language/ref/LongestCommonSubsequencePositions.html.
Wolfram Research (2015), LongestCommonSubsequencePositions, Wolfram Language function, https://reference.wolfram.com/language/ref/LongestCommonSubsequencePositions.html.
CMS
Wolfram Language. 2015. "LongestCommonSubsequencePositions." Wolfram Language & System Documentation Center. Wolfram Research. https://reference.wolfram.com/language/ref/LongestCommonSubsequencePositions.html.
Wolfram Language. 2015. "LongestCommonSubsequencePositions." Wolfram Language & System Documentation Center. Wolfram Research. https://reference.wolfram.com/language/ref/LongestCommonSubsequencePositions.html.
APA
Wolfram Language. (2015). LongestCommonSubsequencePositions. Wolfram Language & System Documentation Center. Retrieved from https://reference.wolfram.com/language/ref/LongestCommonSubsequencePositions.html
Wolfram Language. (2015). LongestCommonSubsequencePositions. Wolfram Language & System Documentation Center. Retrieved from https://reference.wolfram.com/language/ref/LongestCommonSubsequencePositions.html
BibTeX
@misc{reference.wolfram_2025_longestcommonsubsequencepositions, author="Wolfram Research", title="{LongestCommonSubsequencePositions}", year="2015", howpublished="\url{https://reference.wolfram.com/language/ref/LongestCommonSubsequencePositions.html}", note=[Accessed: 09-July-2025
]}
BibLaTeX
@online{reference.wolfram_2025_longestcommonsubsequencepositions, organization={Wolfram Research}, title={LongestCommonSubsequencePositions}, year={2015}, url={https://reference.wolfram.com/language/ref/LongestCommonSubsequencePositions.html}, note=[Accessed: 09-July-2025
]}