MATLAB: How to Compare strings

compare strings

Hello,

I need to compare strings and sort in (even in alphabetical order) but without using

the sort code.

I run a code and I get the error message:

Undefined function or method 'gt' for input arguments of type 'cell'.

Error in ==> Untitled3 at 16 if stock(b)>stock(b+1)

Can anyone help on how to solve this or how to compare strings, or how to convert strings to numbers in order to compare them?

Many thanks

Panos

Best Answer

You want to operate on the cell elements, not on scalar cells:

if stock(b) > stock(b+1)
% ==>
if stock{b} > stock{b+1}  % Curly braces!

This works, if both strings have the same length. A conversion to a numerical is not needed. If the strings have different length, pad the shorter one with zeros:

char0 = char(0);
s1 = stock{b};
s2 = stock{b+1};
len1 = length(s1);
len2 = length(s2);
if len1 > len2
  s2 = [s2, char0(1, len1 - len2)];
elseif len2 > len1
  s1 = [s1, char0(1, len2 - len1)];
end
if s1 > s2 ...

Related Solutions

MATLAB: How to compare the content of two strings in a cell in matlab

The documentation for both of strcmp and strcmpi clearly states that they accept cell arrays of strings as the inputs:

>> A = {'my_string'};
>> B = {'my_string'};
>> strcmp(A,B)
ans =
     1

It may be that your indexing is not working properly. Can you please give more details about the variables s1 and s2: their class, size and contents would be useful. Or perhaps you have nested cell arrays? In order to help you any further, we need to know about those variables!

This might be worth reading too:

http://blogs.mathworks.com/loren/2006/06/21/cell-arrays-and-their-contents/

MATLAB: How to use if statement in cells

It is not clear exactly what format your "binary" data are in, I assumed that they are strings. This script creates the matrix Z as you indicate:

B = {'00','10','11','10','11';...
     '01','01','01','01','11';...
     '10','00','01','00','01';...
     '10','10','01','01','11';...
     '10','10','10','00','10'};
S1 = [21;23;28;25;43];
S2 = [96;85;78;65;76];
%
C = cellfun(@bin2dec,B)>1.5;
[r,~] = find(C);
Z(C) = S1(r);
[r,~] = find(~C);
Z(~C) = S2(r);
Z = reshape(Z,size(C))

When I run the script, it display this in my command window:

Z =
      96    21    21    21    21
      85    85    85    85    23
      28    78    78    78    78
      25    25    65    65    25
      43    43    43    76    43

EDIT: For slightly more compact code, this is equivalent:

C = cellfun(@bin2dec,B)>1.5;
Z(C) = S1(1+rem(find(C)-1,size(C,1)));
Z(~C) = S2(1+rem(find(~C)-1,size(C,1)));
Z = reshape(Z,size(C))

Best Answer

Related Solutions

MATLAB: How to compare the content of two strings in a cell in matlab

MATLAB: How to use if statement in cells

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