Convert a string in char to array in MATLAB

Question

I have a list of strings in a char array:

'gvs(0.000000000000000e+000, 1.601985139535780e+002)'
'gvs(-5.000000000000000e-005, 1.365231866954370e+002)'
'gvs(-1.000000000000000e-004, 1.169431404340180e+002)'
'gvs(-5.000000000000000e-004, 3.187711314514890e+001)'
'gvs(-2.000000000000000e-004, 8.589930648472340e+001)'

Which I am trying to convert to an array of just the numbers (ignoring gvs, the comma and the brackets), but I can't quite work out what I'm doing wrong?

cols = length(Variables) + length(Parameters);
% currently unused
rows = length(Results);

for a = 1:rows;
    Res(a,:) = sscanf ((Results{a,1}(1,:)),'%*s %f %f');
end

I've also tried textscan, but I can't get that to work right either

for a = 1:rows;
    Res = cell (textscan ((Results{a,1}(1,:)),'%*s %f %f','Delimiter', {'(',' '},'MultipleDelimsAsOne',1));
end

Any help much appreciated!

Thanks

The problem here is that %*s reads characters until the first whitespace. What you need is to explicitly match the gvs string (including the parentheses). Also, there's really no point for the (1, :) indexing, just use Results{a, 1} instead. — Eitan T
– Eitan T, Commented Jul 11, 2013 at 11:20

Mohsen Nosratinia · Accepted Answer · 2013-07-11 11:06:38Z

2

Replace

Res(a,:) = sscanf ((Results{a,1}(1,:)),'%*s %f %f');

with

Res(a,:) = sscanf ((Results{a,1}(1,:)),'gvs(%f, %f)');

answered Jul 11, 2013 at 11:06

Mohsen Nosratinia

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2 Comments

Laurengineer Over a year ago

When I do that I get "Conversion to cell from double is not possible." error? If I remove the (a,:) after Res, then I get: Res = -0.0002 85.8993 Which seems to be getting there, but only the last row...

Laurengineer Over a year ago

Ah, I fixed it Res{a,1} = sscanf ((Results{a,1}),'gvs(%f, %f)')';

Oleg · Accepted Answer · 2013-07-11 11:25:13Z

2

Assuming you have a char array (not a cellstring):

s = ['gvs( 0.000000000000000e+000, 1.601985139535780e+002)'
     'gvs(-5.000000000000000e-005, 1.365231866954370e+002)'
     'gvs(-1.000000000000000e-004, 1.169431404340180e+002)'
     'gvs(-5.000000000000000e-004, 3.187711314514890e+001)'
     'gvs(-2.000000000000000e-004, 8.589930648472340e+001)']

Then you can simply textscan():

data = textscan(s','gvs(%f%f)','CollectOutput',1,'Delimiter',',');
data = data{1}
data =
         0  160.1985
   -0.0001  136.5232
   -0.0001  116.9431
   -0.0005   31.8771
   -0.0002   85.8993

If s is a cellstring, then before calling textscan, convert to char():

s = char(s);

edited Jul 11, 2013 at 11:25

answered Jul 11, 2013 at 11:05

Oleg

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1 Comment

Eitan T Over a year ago

I think Results is a cell array, note the curly braces in the question.

Rody Oldenhuis · Accepted Answer · 2013-07-11 12:32:31Z

0

Considering that your string is almost in MATLAB-array compatible format, you could commit a sin and use evalc:

>> s = {
    'gvs( 0.000000000000000e+000, 1.601985139535780e+002)'
    'gvs(-5.000000000000000e-005, 1.365231866954370e+002)'
    'gvs(-1.000000000000000e-004, 1.169431404340180e+002)'
    'gvs(-5.000000000000000e-004, 3.187711314514890e+001)'
    'gvs(-2.000000000000000e-004, 8.589930648472340e+001)'};

>> C = evalc(['[' regexprep([s{:}], {'gvs\(' '\)'}, {'' ';'}) ']'])

ans =
                         0    1.601985139535780e+002
   -5.000000000000000e-005    1.365231866954370e+002
   -1.000000000000000e-004    1.169431404340180e+002
   -5.000000000000000e-004    3.187711314514890e+001
   -2.000000000000000e-004    8.589930648472340e+001

edited Jul 11, 2013 at 12:32

answered Jul 11, 2013 at 11:26

Rody Oldenhuis

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