Extract float from a filename

Hi all,

I have a list of files in a directory with a name of "time_ xx" where xx is number (for e.g 0.20, 0.41, 0.61, 0.82,...) the number is not does not have a fixed expression. I want like to extract these number and used it for calculation later.

May I know what function can I used to extract the number from a filename without extension?

Thank you.

Answer 1

[DGM]

Well I guess this is one way. There are probably more elegant ways of unpacking the nested cell array and converting to numeric, but this is how I did it.

names = {'time_0.709'
    'time_5.61'
    'time_0.2081'
    'time_45.027'
    'time_90'};

filenums = str2double(regexprep(names,'.*_(?=(\d*\.*)+$)',''))

filenums = 5×1

0.7090 5.6100 0.2081 45.0270 90.0000

This looks for any number between an underscore and the end of each name. The filename prefix is ignored except for the underscore.

I guess if you wanted rely on the prefix, you could alternatively just do:

names = {'time_0.709'
    'time_5.61'
    'time_0.2081'
    'time_45.027'
    'time_90'};

filenums = str2double(strrep(names,'time_',''))

filenums = 5×1

0.7090 5.6100 0.2081 45.0270 90.0000

[K3iTH]

Hi DGM,

Thank you for you help. Both method is very useful. Persoanlly, I seldom use "regexprep" but the second method "strrep" is fast and direct.

Once again, thank you so much!