[Python-ideas] string method count()

[Wes Turner]

On Wednesday, April 25, 2018, Steven D'Aprano <steve at pearwood.info> wrote:

> On Wed, Apr 25, 2018 at 11:22:24AM -0700, Julia Kim wrote:
> > Hi,
> >
> > There’s an error with the string method count().
> >
> > x = ‘AAA’
> > y = ‘AA’
> > print(x.count(y))
> >
> > The output is 1, instead of 2.
>
> Are you proposing that there ought to be a version of count that looks
> for *overlapping* substrings?
>
> When will this be useful?


"Finding a motif in DNA"
http://rosalind.info/problems/subs/

This is possible with re.find, re.finditer, re.findall, regex.findall(,
overlapped=True), sliding window
https://stackoverflow.com/questions/2970520/string-count-with-overlapping-occurrences

n-grams can be by indices or by value.
count = len(indices)
https://en.wikipedia.org/wiki/N-gram#Examples

https://en.wikipedia.org/wiki/String_(computer_science)#String_processing_algorithms

https://en.wikipedia.org/wiki/Sequential_pattern_mining


>
> --
> Steve
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