30 most frequent words with more than 4 letters in a text file

I have to resolve this problem:

Read a large existing text file (you can create one by copying a large text from the browser into notepad and saving with extension .txt). Find the 30 most frequent words with more then 4 letters. (Filter out non-letters)

i've only did this:

clear all; close all; clc;

fid=fopen('text.txt');

text=fread(fid,1000000,'uint8=>char')';

fclose(fid);

How could I finish the problem?

Answer 1

[Cris LaPierre]

See the Analyze Text Data with String Arrays example.

[Maria Elena Lazar]

Thank you!