How can I extract an array of numbers from a text-formatted cell array of strings.

I have read some data from a spreadsheet. The values are times, but formatted with s, m or h as a suffix to indicate seconds, minutes or hours. see example below,

I'd like to convert all of them to seconds, with NaN for the blank ones.

Is there an elegant way to do this?

Like this:

    {'20s'                                        }
    {'15m'                                        }
    {0×0 char                                     }
    {'24s'                                        }
    {0×0 char                                     }
    {'44s'                                        }
    {'3h'                                         }
    {'40m'                                        }
    {'20s'                                        }
    {0×0 char                                     }
    {'14s'                                        }
    

Answer 1

[Stephen23]

C = {'20s';'15m';'';'24s';'';'44s';'3h';'40m';'20s';'';'14s'}

C = 11x1 cell array
    {'20s'   }
    {'15m'   }
    {0x0 char}
    {'24s'   }
    {0x0 char}
    {'44s'   }
    {'3h'    }
    {'40m'   }
    {'20s'   }
    {0x0 char}
    {'14s'   }

F = @(t)prod(sscanf(t,'%f'));
V = cellfun(F,regexprep(C,{'h$','m$','^$'},{' 3600',' 60','NaN'},'emptymatch'))

V = 11x1

20 900 NaN 24 NaN 44 10800 2400 20 NaN

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Answer 2

[Voss]

data = {
    '20s'
    '15m'
    ''
    '24s'
    ''
    '44s'
    '3h'
    '40m'
    '20s'
    ''
    '14s'
    };

C = regexp(data,'(\d+)([hms])','tokens','once');
idx = ~cellfun(@isempty,C);
C = vertcat(C{idx});
val = str2double(C(:,1));
[~,unit] = ismember(C(:,2),{'s','m','h'});
result = NaN(size(data));
result(idx) = val.*60.^(unit-1);

disp(result)

          20
         900
         NaN
          24
         NaN
          44
       10800
        2400
          20
         NaN
          14

Answer 3

[dormant]

Thanks. Both of you helped.