Regexp: different behavior for the same type of expressions

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Giorgos Papakonstantinou
I want to capture everything except the tokens:
name, '_' and '.iv2'
name =
A7122
>> filename'
ans =
'A7122_60a.iv2'
'A7122_60b.iv2'
'A7122_70a.iv2'
'A7122_70b.iv2'
'A7122_90a.iv2'
'A7122_90b.iv2'
'A7122_100.iv2'
'A7122_120.iv2'
I do this:
str=regexp(filename, [ '(?:[^' name '_])\w*(?:[^.iv2])' ], 'match');
And the answer is the following!
>> celldisp(str)
str{1}{1} =
60a
str{2}{1} =
60b
str{3}{1} =
0a
str{4}{1} =
0b
str{5}{1} =
90a
str{6}{1} =
90b
str{7}{1} =
00
str{8} =
{}
I don't understand why regexp has a different behavior for i.e. in filename(1) and filename(3)
  2 个评论
Cedric
Cedric 2013-9-19
编辑：Cedric 2013-9-20
Your mistake is that [^A7122_] doesn't stand for "any six letters expression that is not 'A7122 _'", but instead for "any character which is not in the pool of literals {'A', '7', '1', '2', '_' }". The same applies to [^.iv2]. This is why 70a and 70b for example are not matched, but you get instead 0a and 0b.

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采纳的回答

Vishal Rane
Vishal Rane 2013-9-19
编辑：Vishal Rane 2013-9-19
You can use:
regexprep( filename, [ name, '_|.iv2'], '')
Also
regexp( filename, [ name, '_(\w*).iv2'], 'tokens')

更多回答（1 个）

Andrei Bobrov
Andrei Bobrov 2013-9-19
编辑：Andrei Bobrov 2013-9-19
str = {'A7122_60a.iv2'
'A7122_60b.iv2'
'A7122_70a.iv2'
'A7122_70b.iv2'
'A7122_90a.iv2'
'A7122_90b.iv2'
'A7122_100.iv2'
'A7122_120.iv2'}
cl = regexp(str,'(?<=_)\w*(?=\.)','match');
out = cat(1,cl{:});
  2 个评论
Andrei Bobrov
Andrei Bobrov 2013-9-20
Please read about regexp, parts:
- Regular expression :
about
Metacharacters ( \w ),
Quantifiers ( expr* ),
Lookaround Assertions ( expr(?=test) and (?<=test)expr )

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