- length(List(:,1)) wastes time with creating the vector List(:,1). Prefer: size(List, 1)
- cellfun('isempty', ...) is faster than |cellfun(@isempty, ...)
Problems finding exact match for a string
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Hello,
I would like to match a string in a list of other strings (cell array). My problem is that in using regexpi or regexp, it misidentifies the location of the string if it finds it as a substring. For example
GN= {‘EC2020’}; In looking at a cell array of strings, GN will be found in the string ‘EC2020.1’
I do not want it to match with this expression because this is string stands for something different. I simply want to exact match EC2020 without including EC2020.1 as a hit. Some more details of this is example:
GN = {'EC2020'};
List = {'EC1919'; 'EC2020'; 'EC2020.1'};
dList = length(List(:,1));
pds = cell(1,dL);
j = 1;
for i = 1:dList
c = find(~cellfun(@isempty,regexpi(List(i,:),GN)));
if ~isempty(c)
pds(j)= List(i,1);
j = j + 1;
end
end
Any help would be greatly appreciated!
0 Comments
Accepted Answer
Jan
on 24 Aug 2017
Edited: Jan
on 24 Aug 2017
What about strcmp:
GN = {'EC2020'};
List = {'EC1919'; 'EC2020'; 'EC2020.1'};
index = find(strcmp(List, GN{1}))
any(strcmp(List, GN{1})) looks much easier than
~isempty(find(~cellfun(@isempty,regexpi(List(i,:),GN))))
Your output pds is a cell of the same size as List, and it contains the searched strings as often, as they are found. This can be done without a loop by:
pds = List(strcmp(List, GN{1}));
Notes:
More Answers (3)
Walter Roberson
on 24 Aug 2017
Because of your decimal points, you should be using regexptranslate() to prepare your target strings.
You can force exact matches of complete strings by putting '^' before the prepared string and '$' after it. However, if that is your purpose, you should consider using strcmp as Jan shows.
If you are looking for an match with any one of a number of strings, then you should consider using ismember(). If you need something more complicated, then you can consider
temp = regexptranslate('escape', GN);
pattern = [ '^(', strjoin(temp, '|'), '$' ];
match_information = regexp(List, pattern, 'match');
Or perhaps
temp = regexptranslate('escape', GN);
pattern = [ '^(?<word>', strjoin(temp, '|?<word>'), ')$' ];
match_struct = regexp(List, pattern, 'names');
{match_struct.name}
John BG
on 24 Aug 2017
Hi J M
From the additional information
for a much larger set of info ..
The GN variable represents a list of values ..
that includes both decimal values and non-decimal values.
the best way to obtain matching strings is with intersect
List={'EC1919';'EC2020';'EC2020.1';'EC1919.21';'EC1234'};
GN={'EC2020','EC3456','EC1919'};
A=intersect(List,GN)
A =
2×1 cell array
'EC1919'
'EC2020'
if you find this answer useful would you please be so kind to consider marking my answer as Accepted Answer?
To any other reader, if you find this answer useful please consider clicking on the thumbs-up vote link
thanks in advance
John BG
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