Cell of Strings, using cell2mat gives Dimensions of arrays being concatenated are not consistent.

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Sage Hayes 2022-4-14

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评论： Voss 2022-4-14

I've got an excel document with lots of fancy editing that I'm trying to do processing on.

I've imported it as a table since rows may change over time and I'd like to be able to use row names to reference table data. I need to make some changes to the first column in order to use T.Properties.RowNames

Here's been the process so far, Import as table > grab the first column with table2array > this gives an array of cells > replace all the 0x0 char empty cells with a unique string > use cell2mat to convert to an array of strings > pass string array to T.Properties.RowNames

however, when I go to use cell2mat I get the error "Dimensions of arrays being concatenated are not consistent."

can't figure out what's causing it, I tried using which was a fix I found elsewhere to check for empty cells that may be the cause:

isEm = cellfun( @isempty, namerows ) ;
 data = cell2mat( namerows(~isEm) ) ;

but the cell2mat function in this fix returns the same error

Any help would be appreciated

Here's my code:

%impot table, extract first column, convert to an array of cells
T = readtable('3-22 week 3.xlsx');
namerows = T(:,1);
namerows = table2array(namerows);
%array of numbers to be passed to sprintf to ensure each row has a unique
%name
nullname = 1:length(namerows);
%replace any unnamed rows with a string
for n = 1:length(namerows)
    if (namerows{n,1} == "")
        namerows{n,1} = sprintf('null%d',nullname(n))
    end
end
%double check there are no empty cells
isEm = cellfun( @isempty, namerows ) ;
data = cell2mat( namerows(~isEm) ) ; %CODE FAILS HERE
namerows = cell2mat(namerows)

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Stephen23 2022-4-14

@Sage Hayes: please upload a sample data file by clicking the paperclip button.

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Answer 1

Voss 2022-4-14

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在 MATLAB Online 中打开

I'm not sure why you want to use cell2mat to convert a cell array of character vectors to an array of strings. You can use string for that:

% cell array of character vectors:
namerows = repmat({'name'},10,1);
namerows{4} = ''; % some are empty
%replace any unnamed rows with a string
nullname = 1:length(namerows);
for n = 1:length(namerows)
    if (namerows{n,1} == "")
        namerows{n,1} = sprintf('null%d',nullname(n));
    end
end
disp(namerows) % none are empty -> removing empties before cell2mat won't matter
    {'name' }
    {'name' }
    {'name' }
    {'null4'}
    {'name' }
    {'name' }
    {'name' }
    {'name' }
    {'name' }
    {'name' }
try
    namerows = cell2mat(namerows)
catch ME
    disp(ME.message);
    namerows = string(namerows)
end
Dimensions of arrays being concatenated are not consistent.
namerows = 10×1 string array
    "name"
    "name"
    "name"
    "null4"
    "name"
    "name"
    "name"
    "name"
    "name"
    "name"

cell2mat on a cell array of character vectors will attempt to concatenate the character vectors, so they have to have consistent sizes:

cell2mat({'this_';'is_ok'})
ans = 2×5 char array
    'this_'
    'is_ok'
cell2mat({'this_';'is_not'})
Error using cat
Dimensions of arrays being concatenated are not consistent.

Error in cell2mat (line 83)
            m{n} = cat(1,c{:,n});

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Sage Hayes 2022-4-14

Thank you! solved. Didn't realize that the contents of each cell were of type char, I thought each cell was a string.

Voss 2022-4-14

在 MATLAB Online 中打开

You're welcome!

If it had been a cell array of strings, you would've gotten a different error (but using string to convert to a string array would still work):

% cell array of *strings*:
namerows = repmat({"name"},10,1);
namerows{4} = ""; % some are empty
%replace any unnamed rows with a string
nullname = 1:length(namerows);
for n = 1:length(namerows)
    if (namerows{n,1} == "")
        namerows{n,1} = sprintf('null%d',nullname(n)); % this is a character vector
    end
end
disp(namerows) % some strings, some character vectors
    {["name"]}
    {["name"]}
    {["name"]}
    {'null4' }
    {["name"]}
    {["name"]}
    {["name"]}
    {["name"]}
    {["name"]}
    {["name"]}
try
    % the error you'd get here is:
    % "All contents of the input cell array must be of the same data type."
    namerows = cell2mat(namerows)
catch ME
    disp(ME.message);
    % this works the same whether it's a cell array of character vectors or
    % strings (or some of both)
    namerows = string(namerows)
end
All contents of the input cell array must be of the same data type.
namerows = 10×1 string array
    "name"
    "name"
    "name"
    "null4"
    "name"
    "name"
    "name"
    "name"
    "name"
    "name"

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Cell of Strings, using cell2mat gives Dimensions of arrays being concatenated are not consistent.

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Cell of Strings, using cell2mat gives Dimensions of arrays being concatenated are not consistent.

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