How to search a word both uppercase and lowercase given a specified string?

MIM Maestro puts volume data inside the table variable names:

Rectum (4)(Volume: 57.77)  Bladder (5)(Volume: 139.40)

However, sometimes the name is lowercase, e.g. 'bladder'. If one wishes to pull the volume '139.40' from the CSV file, how can one search for both 'Bladder' and 'bladder' in a single query given an input string?

The following function only searches the entered string with regexp; if the input organ string is 'Bladder', doesn't regexp neglect 'bladder'?

function output = GetVolumesFromDVH(organ)

   [omitting code to loop through multiple files...]
   searchstring = [organ,'_'];
   [...]
       output(fileloop) = GetOrgVol(filepath,searchstring);
   [...]
end

function volume = GetOrgVol(filepath,searchstring)
 % get list of variable names
 opts = detectImportOptions(filepath, 'NumHeaderLines', 1);
 % we find the column containing the organ volume
 OrganSearching = regexp(opts.VariableNames,searchstring);
 for loop = 1:numel(opts.VariableNames)
     if OrganSearching{loop} == 1
         index = loop;
     end
 end
 % extract volume from said string
 volume = extractAfter(opts.VariableNames{index},'Volume_');
 volume = sscanf(strrep(volume,'_','.'),'%f');
end

[Daniel Bridges]

I wonder if one can use the StringToUpper function (C library?) together with an 'or'-type command and lowercase input string to search both terms.

Answer 1

[Star Strider]

The regexpi (link) function is the case-insensitive version of regexp.

[Daniel Bridges]

Thank you! I suspected it was something "easy". I'm embarrassed to not have taken a closer look at the related functions in the documentation.

That increases my MATLAB R2017b runtime from 17 s to 25 s (searching 40 files, storing 40 volumes in a column vector), but I suppose it cannot be helped, that it's in fact searching multiple times for each variant. (Right? e.g. given 'rectum': 'Rectum', 'rEctum', 'reCTum', etc.)

I'm downloading R2018a now, wondering if it will be any faster.

[Star Strider]

As always, my pleasure!

Thanks for the info on R2018a. I didn’t know it was available. (It wasn’t when I checked a earlier this week.) I’ll follow your lead.

[Daniel Bridges]

R2018a executed it in 6 s rather than 25 s, and clear and trying again it did so in 1 s. Hooray!

Answer 2

[Image Analyst]

Just cast the string to lower and use a lower case template:

if contains(lower(yourString), 'bladder')
    % yourString contains bladder somewhere in it
end

or you might use strcmpi() if you're sure there is no other characters in your string other than the template you're searching for:

if strcmpi(yourString, 'bladder')