Help with text file duplicate and concatenation

Hello I have created a variable from a text file from which I have extrapolated

nuova_variabile =

    '$SDDBT,00004.9,f,0001.5,M,0000.8,F*07'
    '$GPGLL,5340.91664087,N,00713.79587546,E,073418.00,A,D*62'
    '$GPGLL,5340.91360433,N,00713.79468132,E,073420.00,A,D*64'
    '$SDDBT,00004.5,f,0001.4,M,0000.7,F*05004.5,f,0001.4,M,0000.7,F*02'
    '$GPGLL,5340.91207731,N,00713.79413391,E,073421.00,A,D*63'
    '$GPGLL,5340.91056222,N,00713.79354123,E,073422.00,A,D*6E'
    '$SDDBT,00006.5,f,0002.0,M,0001.0,F*06'
    '$GPGLL,5340.90756479,N,00713.79236750,E,073424.00,A,D*61'
    '$SDDBT,00006.8,f,0002.1,M,0001.1,F*0B'
    '$GPGLL,5340.90609055,N,00713.79168827,E,073425.00,A,D*66'
    '$SDDBT,00007.8,f,0002.4,M,0001.3,F*0D'
    '$GPGLL,5340.90462662,N,00713.79106230,E,073426.00,A,D*6C'

I would like to remove the $GPGLL duplicate when this happen in sequence, keeping only the first string to have something like this

    '$SDDBT,00004.9,f,0001.5,M,0000.8,F*07'
    '$GPGLL,5340.91664087,N,00713.79587546,E,073418.00,A,D*62'
    '$SDDBT,00004.5,f,0001.4,M,0000.7,F*05004.5,f,0001.4,M,0000.7,F*02'
    '$GPGLL,5340.91207731,N,00713.79413391,E,073421.00,A,D*63'
    '$SDDBT,00006.5,f,0002.0,M,0001.0,F*06'
    '$GPGLL,5340.90756479,N,00713.79236750,E,073424.00,A,D*61'
    '$SDDBT,00006.8,f,0002.1,M,0001.1,F*0B'
    '$GPGLL,5340.90609055,N,00713.79168827,E,073425.00,A,D*66'
    '$SDDBT,00007.8,f,0002.4,M,0001.3,F*0D'
    '$GPGLL,5340.90462662,N,00713.79106230,E,073426.00,A,D*6C'

and after that I would like to write a file were I have the $SDDBT and successive $GPGLL in a single line like this

'$SDDBT......$GPGLL..... '$SDDBT.......$GPGLL....

and so on.....

thanks in advance for you help

Manuela

[mb1400]

sorry like this

'$SDDBT......$GPGLL.....

'$SDDBT.......$GPGLL....

Answer 1

[Azzi Abdelmalek]

b=char(nuova_variabile);
c=cellstr(b(:,1:6));
idx=strcmp(c,'$SDDBT')';
ii=[1 diff(idx)];
out=nuova_variabile(find(ii~=0))

% then add

ne=ceil(numel(out)/2)
out=cellfun(@(x,y) [x ' ' y],out(1:2:end), out(2:2:end),'un',0)
out{1}

Answer 2

[mb1400]

You are a Genius, thank you very much. You saved me days of work!!!!!!

Answer 3

[mb1400]

Ok, Now I am stuck again. Sorry, I may be about to make a very easy question, but I have just started using matlab and starting manipulating string it's not the best. I have replaced the empty spaces in my strings with commas and now I would like to trim all the strings after the last coordinate to have something from this:

'$SDDBT,00006.5,f,0002.0,M,0001.0,F*06,$GPGLL,5340.90756479,N,00713.79236750,E,073424.00,A,D*61'
  '$SDDBT,00006.8,f,0002.1,M,0001.1,F*0B,$GPGLL,5340.90609055,N,00713.79168827,E,073425.00,A,D*66'
  '$SDDBT,00007.8,f,0002.4,M,0001.3,F*0D,$GPGLL,5340.90462662,N,00713.79106230,E,073426.00,A,D*6C'

To this:

'$SDDBT,00006.5,f,0002.0,M,0001.0,F*06,$GPGLL,5340.90756479,N,00713.79236750,E'
'$SDDBT,00006.8,f,0002.1,M,0001.1,F*0B,$GPGLL,5340.90609055,N,00713.79168827,E' '$SDDBT,00007.8,f,0002.4,M,0001.3,F*0D,$GPGLL,5340.90462662,N,00713.79106230,E'

I appreciate the help