Problems finding exact match for a string

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!

Answer 1

[Jan]

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:

• length(List(:,1)) wastes time with creating the vector List(:,1). Prefer: size(List, 1)
• cellfun('isempty', ...) is faster than |cellfun(@isempty, ...)

[J M]

it worked and was very simple thank you!

Answer 2

[Walter Roberson]

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}

[J M]

thank you I will try this one as well to learn from it. Much appreciated

Answer 3

[John BG]

Hi J M

this is John BG <mailto:[e-mail] [e-mail]>

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

<mailto:[e-mail] [e-mail]>

[J M]

I will also try this out. Thanks so much for the reply and suggestion.

Answer 4

[Image Analyst]

Check the length of the strings in addition. The lengths must match.

[J M]

Thanks for the reply. I would but this is actually for a much larger set of info in which I can't just limit it by the size. The GN variable represents a list of values (which I've put into a loop) that includes both decimal values and non-decimal values.