# How to use regex to obtain double values?

47 views (last 30 days)
Struggling in MATLAB on 29 Jul 2022
I have an array of strings which contains some units. I have attahced the array.
unq = ["10 lux";"10lux";"15";"15.0";"15.5 Lux";"15luX";"15lux";"20lux";"36lux";"42lux";"9lux"]
They are put in different format on different days. So, I get 11 unique entries. I used the following code only to keep the numeric part.
trimData = strtrim(unq);
regexData = regexp(trimData,'\d*','Match');
cleanedData = cell(numel(unq),1);
for kk = 1:numel(unq)
if length(regexData{kk}) >= 1
cleanedData{kk} = regexData{kk}(1);
end
end
cleanedData = str2double(string(cleanedData));
I got
cleanedData = [10;10;15;15;15;15;15;20;36;42;9]
I am not getting 15.5 in the resulting array. How do get the numbers in which the digits after decimal place is not '0'? How do I write a regular expression for that?

Walter Roberson on 29 Jul 2022
Edited: Walter Roberson on 29 Jul 2022
Extending to the possibility of fraction values that start with decimal point (with no leading zero), and extending to support negative values
But not extending to exponential format:
unq = ["10 lux";"-10lux";"15";"15.0";"15.5 Lux";"15luX";"15lux";"20lux";"36lux";"42lux";".9lux"]
unq = 11×1 string array
"10 lux" "-10lux" "15" "15.0" "15.5 Lux" "15luX" "15lux" "20lux" "36lux" "42lux" ".9lux"
regexData = regexp(unq, '(-?\d+(\.\d*)?)|(-?\.\d+)', 'match', 'once')
regexData = 11×1 string array
"10" "-10" "15" "15.0" "15.5" "15" "15" "20" "36" "42" ".9"
Struggling in MATLAB on 29 Jul 2022
Exactly what I needed. Thanks a lot, Walter!

### Categories

Find more on Cell Arrays in Help Center and File Exchange

R2022a

### Community Treasure Hunt

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

Start Hunting!