Delete only consecutive repeated string entries from a dataset in matlab

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avantika
avantika 2013-8-29
hi!
I am relatively new to matlab. I have a dataset having three columns, time, pitch and notation. for eg
time pitch notation
2.5725 329.63 G
2.5800 329.63 G
2.5900 311.13 M
2.5900 311.13 M
2.6000 570.40 P
I want to remove duplicates occurring consecutively in the file such that the order remains the same. so the output will be:
time pitch notation
2.5725 329.63 G
2.5900 311.13 M
2.6000 570.40 P
I am currently using matlab 7.9.0 so the first of unique command id not supported. Can anyone tell me how to go about it further.
[EDITED, table formatted, Jan]
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avantika
avantika 2013-8-29
编辑：avantika 2013-8-29
hi!
I am relatively new to matlab. I have a dataset having three columns, time, pitch and notation. for eg
time pitch notation
2.5725 329.63 GM
2.5800 329.63 GM
2.5900 311.13 MM
2.5900 311.13 MM
2.6000 570.40 PM
2.6725 329.63 GM
2.6800 329.63 GM
2.7900 311.13 MM
2.8900 311.13 MM
2.9000 570.40 PM
2.9500 570.40 PM
3.1000 570.40 PM
I want to remove repeated enteries occurring consecutively in the pitch and notation column in the file but the order of the dataset should remain the same. so the output will be:
time pitch notation
2.5725 329.63 GM
2.5900 311.13 MM
2.6000 570.40 PM
2.6725 329.63 GM
2.7900 311.13 MM
2.9000 570.40 PM
Jan
Jan 2013-8-30
编辑：Jan 2013-8-30
I still do not understand the empty lines and the type of the input is not explained here. Is this a text file, a cell containing strings, or or is pitch a field of a struct, which contains a double vector?
What should happen for:
2.5725 329.63 GM
2.5800 329.63 GM
2.5725 329.63 GM
2.5800 329.63 GM
So does "consecutively" mean the position in the array or should a line vanish, if there is any equal set of values before, even if other lines appear in between?
I assume that the solution is very easy, if you define the wanted procedure and the class of the input exactly.

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Andrei Bobrov
Andrei Bobrov 2013-8-29
编辑：Andrei Bobrov 2013-8-30
C ={ 'time' 'pitch' 'notation'
2.5725 329.63 'GM'
2.5800 329.63 'GM'
2.5900 311.13 'MM'
2.6000 570.40 'PM'
2.6725 329.63 'GM'
2.6800 329.63 'GM'
2.7900 311.13 'MM'
2.8900 311.13 'MM'
2.9000 570.40 'PM'
2.9500 570.40 'PM'
3.1000 570.40 'PM'};
d = cell2dataset(C); % your dataset - array
[~,~,ii] = unique(d.notation);
out = d([true;diff(ii)~=0],:);
ADD without dataset array
C ={ 'time' 'pitch' 'notation'
2.5725 329.63 'GM'
2.5800 329.63 'GM'
2.5900 311.13 'MM'
2.6000 570.40 'PM'
2.6725 329.63 'GM'
2.6800 329.63 'GM'
2.7900 311.13 'MM'
2.8900 311.13 'MM'
2.9000 570.40 'PM'
2.9500 570.40 'PM'
3.1000 570.40 'PM'};
[ii,ii,ii] = unique(C(2:end,3));
out = C([true(2,1);diff(ii)~=0],:);
ADD 2
scale = {'GM';'PM'};
[~,ii] = ismember(C(2:end,3),scale);
i1 = ii > 0;
C1 = C(i1,:);
out = C1([true(2,1);diff(ii(i1))~=0],:);
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avantika
avantika 2013-9-2
HI
I get an error when i use the commands given by you for ismember:
scale = {'NL';'NM';'NU';'RL';'RM';'RU';'GL';'GM';'GU';'mL';'mM';'mU';'DL';'DM';'DU';'SL';'SM';'SU';'PL';'PM';'PU';};
>> [~,ii] = ismember(C(2:end,3),scale);
i1 = ii > 0;
C1 = C(i1,:);
out2 = C1([true(2,1);diff(ii(i1))~=0],:);
??? Error using ==> dataset.subsref at 82 Dataset array subscripts must be two-dimensional.
Error in ==> ismember at 78 found = find(a(i)==s(:)); % FIND returns indices for LOC.

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Simon
Simon 2013-8-29
Hi!
I don't understand why the second entry is removed. Is a "duplicate" defined if all three columns match or only the second and third?
Does the unique command in 7.9 support rows? Like
b = unique(A, 'rows')
Does your data set consist of single lines for each entry? You could try to put each data set as a string in a cell array and use unique of the cell array.
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Simon
Simon 2013-8-29
Hi!
Try it with a cell array of strings, as proposed.
The unique command has additional return values that contain the relation between the sorted output and the input. Check the documentation for more information.
avantika
avantika 2013-8-29
编辑：avantika 2013-8-29
hi!
i checked the class of dataset before the conversion to cell array of strings .
class(ds3.pitch)
ans =
double
class(ds3.time)
ans =
double
class(ds3.notation)
ans =
cell
I am not able to convert it to cell array of strings.

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