Problems finding exact match for a string

33 次查看（过去 30 天）
J M
J M 2017-8-23
评论： J M 2017-8-24
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!

请先登录，再回答此问题。

采纳的回答

Jan
Jan 2017-8-24
编辑：Jan 2017-8-24
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, ...)

更多回答（3 个）

Walter Roberson
Walter Roberson 2017-8-24
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}
  1 个评论
J M
J M 2017-8-24
thank you I will try this one as well to learn from it. Much appreciated

请先登录，再进行评论。

John BG
John BG 2017-8-24
Hi J M
this is John BG <mailto:jgb2012@sky.com jgb2012@sky.com>
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:jgb2012@sky.com jgb2012@sky.com>
Image Analyst
Image Analyst 2017-8-23
Check the length of the strings in addition. The lengths must match.
  1 个评论
J M
J M 2017-8-23
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.

请先登录，再进行评论。

类别

在 Help Center 和 File Exchange 中查找有关 Characters and Strings 的更多信息

标签

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Translated by