How can i compare two strings by their alphabetical order

Denememe (view profile)

on 1 Dec 2016
Latest activity Edited by Jomar Bueyes

Jomar Bueyes (view profile)

on 23 Aug 2019
I want to write a function which will compare two strings by their alphabetical order. The function should give an output '-1' if the first string is 'a' and second is 'b'. I couldn't do that with strcmp Thank you

James Tursa

James Tursa (view profile)

on 1 Dec 2016
Please give a few more examples so we are sure what your function is supposed to do.
Denememe

Denememe (view profile)

on 1 Dec 2016
function output = strCompare(s1,s2)
ls1=length(s1);
ls2=length(s2);
if ls1<ls2
for i=1:ls1
if s1(i)<s2(i)
output = [-1];
elseif s1(i)>s2(i)
output = ;
else
output = ;
end
end
elseif ls1>=ls2
for i=1:ls2
if s1(i)<s2(i)
output = [-1];
elseif s1(i)>s2(i)
output = ;
else
output = ;
end
end
end
end
I wrote this function but i want to have an output '1' when s1 = 'America' and s2='A' I take '0' when i do that

dpb (view profile)

on 1 Dec 2016
Edited by Walter Roberson

Walter Roberson (view profile)

on 2 Dec 2016

>> 'a'-'b'
ans =
-1
>>
may give you some ideas??? Or, instead of reinventing the wheel,
lexcmp from File Exchange probably does what you're looking for...

Answer by Jomar Bueyes

Jomar Bueyes (view profile)

on 23 Aug 2019
Edited by Jomar Bueyes

Jomar Bueyes (view profile)

on 23 Aug 2019

I know this question is old. But I wrote a the function below that does what Denememe wants.
function seg = arraySortCriterion(a, b)
% arraySortCriterion returns -1, 0, 1 depending of how a,b must be sorted
%
% SYNTAX:
% seg = arraySortCriterion(a, b);
%
% DESCRIPTION:
% seg = arraySortCriterion(a, b);
% Returns;
% -1 if a must precede b when sorted
% 1 if b must precede a when sorted
% 0 if a and b can be in either order
%
% For arrays and strings, the function compares element by element
% until it finds an element such that a(k) ~= b(k) and returns
% -1 if a(k) < b(k)
% 1 if a(k) > b(k)
% If the two strings or arrays are equal up to the length of the
% shortest one, the shorter array or string goes first in when
% sorted. This is consistent with how Matlab, Python, and Perl sort
% this of strings of different lengths that are equal up to the
% length of the shortest one.
% Author/Date
% Jomar Bueyes
%
% Copyright 2019 Jomar Bueyes
Na = numel(a);
Nb = numel(b);
for k = 1:min(Na, Nb)
seg = sign(a(k) - b(k));
if seg ~= 0
return;
end
end
% ..The two strings/arrays are equal up to the length of the shortest one
seg = sign(Na-Nb); % This places the shortest one first.
return
end