Macro for detect and list palindromes and repeats in letters/numbersstring

  • Thread starter Luciano Paulino da Silva
  • Start date
L

Luciano Paulino da Silva

Dear all,
I am looking to detect palindromes (sentence or number or other
sequence of units that can be read the same way in either direction)
and repeats (sequences of letters or numbers which are repeating at
least twice within a string) in some strings containing between
20-5000 letters. Has somebody any idea how could I perform that using
an Excel macro? I would like that the string to be evaluated could be
on cell "A1" and that the detected palindromes and repeats could be
listed bellow A2 and C2, respectively; and that the number of times
that they appear in the sentence could be listed bellow cells B2 and
D2, respectively, as the following small example:

QGAGGAAGGAGQ
Palindromes Number Repeats Number
QGAGGAAGGAGQ 1 GA 3
GAG 2 AG 3
GG 2 GAG 2
AA 1 AA 1
GG 2

Somebody could help me?
Thanks in advance,
Luciano
 
R

Rick Rothstein

What is the "rule" for forming the included (smaller) palindromes? For
example, why isn't AA, GAAG, GGAAGG, etc. considered included palindromes?
Is the rule "only from one of the mirrored sides"? If so, why do you count
the "repeats" from either of the mirrored sides?
 
B

Barb Reinhardt

There is no need to post this multiple times. If someone can help, they'll
answer the other question.
 
L

Luciano Paulino da Silva

Thank you very much Rick.
In fact, I forgot to talk about that. You are right, and I forgot some
of the potential palindromes, including AA, GAAG and GGAAGG. I needs
of all palindromes that could be generated for a given string. In some
case, they will be subsequences of other palindromes. It is necessary
include palindromes from 2 to any size. For palindromes it is
necessary only count them from one mirroed side since the other side
will be identical.
The repeats will be characterized by any sequence (from 2 to any size)
that appear at least 2 times in the string. In fact, AA is not a
repeat, since it appeared only one time.
Thank you for your observations,
Luciano
 

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