Matlab matrix

I have a question I have the matrix (example)

ID1     54     65
ID2     45     48
ID3     23     43
ID4     32     24
ID5     75     23
ID6     87     45

(real size is about 2000 strings) I need to find a string where 23 43 and after that show ID (there maybe several IDs)

thank you Dmitry

[Andrew Newell]

Is each ID on a separate line?

[Dmitry]

yep , each

Answer 1

[Fangjun Jiang]

Along the line of this code, depending on your data format.

ID={'ID1','ID2','ID3','ID5','ID6'}.';
Col2=[54 45 23 32 75 87].';
Col3=[65 48 43 24 23 45].';

Index=and(Col2==23,Col3==43);
SelectedID=ID(Index);

[Andrew Newell]

But first you need to read it from a file, I presume. You could use something like this:

fid = fopen('testfile.m');

C = textscan(fid,'%s %d %d');

fclose(fid);

ID = C{1}; Col2 = C{2}; Col3 = C{3};

Index=and(Col2==23,Col3==43);

SelectedID=ID(Index);

(Note there is a typo in Fangjun's second last line)

[Fangjun Jiang]

Thank you Andrew!

[Dmitry]

Thank you, but i have one more question.

I have 1000 files (studentIDs) every file has two parameters ( subject1 , subject2 )

every parameter look like

...... day | mark

31.07.2011 | 5

31.07.2011 | 3

31.07.2011 | 5

31.07.2011 | 2

31.07.2011 | 5

I need to write a script which can find "5" in subject1, and show me day and StudentID )

[Fangjun Jiang]

It is similar. Once you read in the data, use logical index, index=subject1==5, or linear index, index=find(subject1==5), and then FoundStudent=StudentID(index). find() also have options to find first, or last, or any number of instance.

Answer 2

[Andrei Bobrov]

ID = {'ID1'
'ID2'
'ID3'
'ID4'
'ID5'
'ID6'}
data = [54     65
45     48
23     43
32     24
75     23
87     45]
out = ID(ismember(data,[23 43],'rows'))