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strfind first occurrence.

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Pramit Biswas
Pramit Biswas el 19 de Mayo de 2016
Comentada: Peter el 27 de Sept. de 2019
str = 'Find the starting indices of a pattern in a character vector'; k = strfind(str,'in') gives, k = 2 15 19 40
any shortcut/direct way to get the first occurrence only. Here in this case: k = 2;

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Guillaume
Guillaume el 19 de Mayo de 2016
You could use regexp with the 'once' option:
k = regexp(str, 'in', 'once')
However, note that some characters have special meanings in regular expression, so if your search string is completely arbitrary you can't just replace strfind with regexp. For safety you can regexptranslate the search string.
On the other hand, what's stopping you from writing:
k = strfind(str, 'in); k = k(1);
If writing two instructions instead of one bother you, you can always create your own function:
function location = strfindfirst(lookin, lookfor)
location = strfind(lookin, lookfor);
if ~isempty(idx)
location = location(1);
end
end
  1 comentario
Peter
Peter el 27 de Sept. de 2019
While the suggested answer works, it is inefficient. If you have very long strings to search through and/or have many strings to search, finding all of the occurances first, and then truncating the answer to just to first one, is a waste. Its too bad that strfind doesn't have a 'first' or 'last' option like 'find'.

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