Using strfind or regexp in cell

Hi!

I have the following example data:

'METAR ESSA 202008010020Z 28003KT CAVOK 10/09 Q1017 NOSIG'

'METAR ESSA 202008010050Z 27004KT CAVOK 10/09 Q1017 NOSIG'

'METAR ESSA 202008010120Z 27004KT CAVOK 09/09 Q1017 NOSIG'

'METAR ESSA 202008010150Z 28004KT CAVOK 10/09 Q1017 NOSIG'

'METAR ESSA 202008010220Z 29003KT CAVOK 09/09 Q1017 NOSIG'

'METAR ESSA 202008010250Z 29003KT CAVOK 09/09 Q1017 NOSIG'

'METAR ESSA 202008010320Z 28003KT CAVOK 09/09 Q1017 NOSIG'

'METAR ESSA 202008010350Z 03002KT CAVOK 12/12 Q1017 NOSIG'

'METAR ESSA 202008010420Z 29002KT CAVOK 11/11 Q1017 NOSIG'

'METAR ESSA 202008010450Z 34004KT CAVOK 13/12 Q1017 NOSIG'

'METAR ESSA 202008010520Z 30004KT CAVOK 15/13 Q1017 NOSIG'

'METAR ESSA 202008010550Z 32004KT CAVOK 16/13 Q1017 NOSIG'

'METAR ESSA 202008010620Z 34003KT CAVOK 17/14 Q1017 NOSIG'

'METAR ESSA 202008010650Z VRB03KT CAVOK 18/14 Q1017 NOSIG'

'METAR ESSA 202008010720Z VRB03KT CAVOK 19/13 Q1017 NOSIG'

'METAR ESSA 202008010750Z 05004KT 030V100 CAVOK 20/10 Q1017 NOSIG'

'METAR ESSA 202008010820Z 02004KT 350V060 CAVOK 20/09 Q1017 NOSIG'

'METAR ESSA 202008010850Z 03004KT 360V070 CAVOK 21/10 Q1018 NOSIG'

'METAR ESSA 202008010920Z 03004KT 360V090 CAVOK 21/08 Q1017 NOSIG'

'METAR ESSA 202008010950Z 03005KT 360V080 CAVOK 22/08 Q1017 NOSIG'

'METAR ESSA 202008011020Z 05005KT 010V090 CAVOK 22/08 Q1017 NOSIG'

I would like to use strfind or regexp to extract the group '10/09' from each string. This is the temperature and dewpoint of a certain airport at a certain time. I would also like to store the third group '202008010020Z' which is the date and time together with the temperature and dewpoint separated in a matrix. Could you please help me with this? I'm a bit stuck at the moment.

Best regards

Linus

Answer 1

[Rik]

Your intuition that you can use a regular expression is correct:

data={...
    'METAR ESSA 202008010020Z 28003KT CAVOK 10/09 Q1017 NOSIG'
    'METAR ESSA 202008010050Z 27004KT CAVOK 10/09 Q1017 NOSIG'
    'METAR ESSA 202008010120Z 27004KT CAVOK 09/09 Q1017 NOSIG'
    'METAR ESSA 202008010150Z 28004KT CAVOK 10/09 Q1017 NOSIG'
    'METAR ESSA 202008010220Z 29003KT CAVOK 09/09 Q1017 NOSIG'
    'METAR ESSA 202008010250Z 29003KT CAVOK 09/09 Q1017 NOSIG'
    'METAR ESSA 202008010320Z 28003KT CAVOK 09/09 Q1017 NOSIG'
    'METAR ESSA 202008010350Z 03002KT CAVOK 12/12 Q1017 NOSIG'
    'METAR ESSA 202008010420Z 29002KT CAVOK 11/11 Q1017 NOSIG'
    'METAR ESSA 202008010450Z 34004KT CAVOK 13/12 Q1017 NOSIG'
    'METAR ESSA 202008010520Z 30004KT CAVOK 15/13 Q1017 NOSIG'
    'METAR ESSA 202008010550Z 32004KT CAVOK 16/13 Q1017 NOSIG'
    'METAR ESSA 202008010620Z 34003KT CAVOK 17/14 Q1017 NOSIG'
    'METAR ESSA 202008010650Z VRB03KT CAVOK 18/14 Q1017 NOSIG'
    'METAR ESSA 202008010720Z VRB03KT CAVOK 19/13 Q1017 NOSIG'
    'METAR ESSA 202008010750Z 05004KT 030V100 CAVOK 20/10 Q1017 NOSIG'
    'METAR ESSA 202008010820Z 02004KT 350V060 CAVOK 20/09 Q1017 NOSIG'
    'METAR ESSA 202008010850Z 03004KT 360V070 CAVOK 21/10 Q1018 NOSIG'
    'METAR ESSA 202008010920Z 03004KT 360V090 CAVOK 21/08 Q1017 NOSIG'
    'METAR ESSA 202008010950Z 03005KT 360V080 CAVOK 22/08 Q1017 NOSIG'
    'METAR ESSA 202008011020Z 05005KT 010V090 CAVOK 22/08 Q1017 NOSIG'};

A=regexp(data,'\d{12}[A-Z]','match');A=[A{:}]

A = 1×21 cell array
    {'202008010020Z'}    {'202008010050Z'}    {'202008010120Z'}    {'202008010150Z'}    {'202008010220Z'}    {'202008010250Z'}    {'202008010320Z'}    {'202008010350Z'}    {'202008010420Z'}    {'202008010450Z'}    {'202008010520Z'}    {'202008010550Z'}    {'202008010620Z'}    {'202008010650Z'}    {'202008010720Z'}    {'202008010750Z'}    {'202008010820Z'}    {'202008010850Z'}    {'202008010920Z'}    {'202008010950Z'}    {'202008011020Z'}

B=regexp(data,'\d{2}/\d{2}','match');B=[B{:}]

B = 1×21 cell array
    {'10/09'}    {'10/09'}    {'09/09'}    {'10/09'}    {'09/09'}    {'09/09'}    {'09/09'}    {'12/12'}    {'11/11'}    {'13/12'}    {'15/13'}    {'16/13'}    {'17/14'}    {'18/14'}    {'19/13'}    {'20/10'}    {'20/09'}    {'21/10'}    {'21/08'}    {'22/08'}    {'22/08'}

[Stephen23]

Note: you can easily avoid the superfluous nested cell array by specifying the 'once' option.

[Linus Dock]

Thanks that's great!

Now I'm making some progress :)

Now I have a follow-up question,

How do I get the values into one cell.

I would like to have an output as a table with:

(Dateandtime, Temperature, Dewpoint) in separate kolumns.

I've tried to modify the above regexpr to sort out the temperature and use the following code to create a table.

How can I organise the output to create a table of the data?

A=regexp(METARresult,'\d{12}[A-Z]','match');A=[A{:}]
B=regexp(METARresult,'\d{2}(?=/)','match');B=[B{:}]
C={A B};
Z=cell2table(C);
writetable(Z,'data.txt');
winopen('data.txt');

Best regards

Linus

[Rik]

You should try to parse the text to the data type you need. Then you can easily put them together. A loop will probably be best. You should not need to write to a file as an intermediate step.