Concatenating a cell array

Hi everyone,

I'm trying to take a large cell array and cut out any rows that have the letters in the first column. This is from an event file for baseball games, and a small example:

'fox-a001' 'Andy Fox' ''

'5' '1' 'K'

'6' '0' 'NP'

'kim-s001' 'Sun-Woo Kim' ''

'6' '0' '8/F'

I would like to delete any rows where the first column isn't a number (for example, the rows 1 and 5 in this example). Since the entire data set is about 12,000 rows long, ideally having a script that can find these values and remove then is ideal. I tried logical operators and ran into errors that the functions wouldn't work with cell arrays, so I'm not sure what to try next. Thanks for any help!

Answer 1

[David Young]

I guess you mean that you would like to delete rows 1 and 4. If that's right, here's one way:

% set up the test data
data = {'fox-a001' 'Andy Fox' ''; ...
    '5' '1' 'K'; ...
    '6' '0' 'NP'; ...
    'kim-s001' 'Sun-Woo Kim' ''; ...
    '6' '0' '8/F'};

% function that defines what is meant by a number. This says a string
% represents a number if every character is a digit, or . or + or -, but
% this can be modified according to what is right for your data.
isnum = @(s) all(ismember(s, '0123456789.+-'));

% use the function to find the row indices where the first entry is a
% number
numrows = cellfun(isnum, data(:,1));

% make a new matrix, retaining only those rows
dataNumsOnly = data(numrows, :);

[Devon]

Sorry yeah, I did mean rows 1 and 4 from that data. Thanks a ton, this did exactly what I needed it to do!

Answer 2

[Guillaume]

I would just use str2double to test if the string is a number. It will return NaN if not. Perform the test on the first column of the cell array:

c = {
  'fox-a001' 'Andy Fox' ''
  '5' '1' 'K'
  '6' '0' 'NP'
  'kim-s001' 'Sun-Woo Kim' ''
  '6' '0' '8/F'};
tf = isnan(str2double(c(:, 1)));
c(tf, :) = [];