Making new matrix with specific rows

The following code as an example, how would I go about making a new separate table with only the rows with a specific value in a column?

ie: How would I go about making the new table with only 'ABC' in the first column?

I've tried the method of using a for loop and manually checking line by line but the file that I actually have to do this for is much larger and takes way too long so I was wondering if there's a faster way, maybe with ':'

A = {
    'ABC'    1.0000    5.5000
    'ABC'    2.0000    1.2000
    'DEF'    3.0000    6.4000
    'ABC'    4.0000    3.7000
    'XYZ'    5.0000    3.6000
    'PQT'    6.0000    9.6000};

Answer 1

[Dyuman Joshi]

A = {
    'ABC'    1.0000    5.5000
    'ABC'    2.0000    1.2000
    'DEF'    3.0000    6.4000
    'ABC'    4.0000    3.7000
    'XYZ'    5.0000    3.6000
    'PQT'    6.0000    9.6000};

%Compare the 1st column of the char array/string 'ABC'
idx = strcmp(A(:,1),'ABC')

idx = 6×1 logical array
   1
   1
   0
   1
   0
   0

%Create the new array corresponding to the indices
B = A(idx,:)

B = 3×3 cell array
    {'ABC'}    {[1]}    {[5.5000]}
    {'ABC'}    {[2]}    {[1.2000]}
    {'ABC'}    {[4]}    {[3.7000]}

Answer 2

[dpb]

Use <logical indexing>, a basic MATLAB syntax/idiom. If this isn't something you're not already familiar with, I'd suggest reading through the <Language Fundamentals> section of the introductory help/documentation.

[Brandon]

Thank you, I will! Sorry if this is a really basic question, I'm at an internship right now and am learning Matlab as I go haha.

[Dyuman Joshi]

I strongly recommend you go through the free MATLAB Onramp tutorial to learn the essentials of MATLAB.

[dpb]

While it seems like wasting time that could be coding; you'll progress towards the end goal far more effectively if you learn at least the rudiments of the language (and its idiosyncracies) first; the time spent either in the "Getting Started" or the "On Ramp" tutorials will pay back the investment many times over.