Omit the brute clearing header
clc;clear all; close all;
It is a waste of time, kills other windows, and has not serious benefit. It is recommended by teachers, which remember to have learned this as pupils also. This is called "Cargo Cult programming".
Avoid global variables, because they are a shot in your knee.
Using "text" as a variable does not let you use the command text() anymore. This is called "shadowing" and a frequent source of unexpected behavior.
String(1:length(String)) is the same as String.
'a':'z' is a vector already. There is no need to included it in [ and ] , because this is Matlab concatenation operator. But you do not concatenate 'a':'z' to anything.
Now the actual problem:
for letter=String(1:length(String)) % < This is not used inside the inner loop
letter=lower(letter); % < So you can omit the outer loop
for alphabet=['a':'z']
A=count(String,alphabet);
vect_A(i)=A; %stock the value
i=i+1;
end
end
Althout the for letter loop is not used at all, the counting is performed as often as the String has characters. So vect_A contains the list of numers of repetitions repeatedly. vect_A has 26 * numel(String) values finally. Therefore assiging the 26 characters as names of the variables of the table cannot work.
Solution: Omit the outer loop.
function get_occurences(String)
vect_A = [];
i = 1;
for alphabet=['a':'z']
A = count(String,alphabet);
vect_A(i)=A; %stock the value
i=i+1;
end
occ_table = array2table(vect_A);
occ_table.Properties.VariableNames = {'a','b','c','d','e','f','g','h','i','j','k','l','m','n','o','p','q','r','s','t','u','v','w','x','y','z'}
end
Or a simplified version:
function get_occurences(String)
CharList = 'a':'z';
vect_A = zeros(1, numel(CharList)); % pre-allocate
for k = 1:numel(CharList)
vect_A(k) = count(String, CharList(k));
end
occ_table = array2table(vect_A);
occ_table.Properties.VariableNames = num2cell(CharList);
end
