How to find complementry sequence within the sequence

Question

[archana.bioinfo87]

Hi,

I have multiple sequences and I want to find the presence of complementary sequence within the sequences.

It's just like find stem-loop structure in a sequence.
Length of complementary sequences should not be greater than 5bp.

library(seqinr)

g33 <- ("ATGCATATAATATAGAGGCAT")
nchar(g33)
a <- c2s(comp(s2c(g33)))
a
all(substr(a, 1, 1)== substr(c2s(comp(s2c(g33))), 20, 20))

But, what if my position go on increasing. I tried for loop but failed. I am using library(stringr) in R

Any help is much appreciated. I am a new learner of R.

Thanks

[zx8754]

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