function x = emailFeatures(word_indices) %EMAILFEATURES takes in a word_indices vector and produces a feature vector %from the word indices % x = EMAILFEATURES(word_indices) takes in a word_indices vector and % produces a feature vector from the word indices. % Total number of words in the dictionary n = 1899; % You need to return the following variables correctly. x = zeros(n, 1); for i = 1:length(word_indices) x(word_indices(i)) = 1; end % ====================== YOUR CODE HERE ====================== % Instructions: Fill in this function to return a feature vector for the % given email (word_indices). To help make it easier to % process the emails, we have have already pre-processed each % email and converted each word in the email into an index in % a fixed dictionary (of 1899 words). The variable % word_indices contains the list of indices of the words % which occur in one email. % % Concretely, if an email has the text: % % The quick brown fox jumped over the lazy dog. % % Then, the word_indices vector for this text might look % like: % % 60 100 33 44 10 53 60 58 5 % % where, we have mapped each word onto a number, for example: % % the -- 60 % quick -- 100 % ... % % (note: the above numbers are just an example and are not the % actual mappings). % % Your task is take one such word_indices vector and construct % a binary feature vector that indicates whether a particular % word occurs in the email. That is, x(i) = 1 when word i % is present in the email. Concretely, if the word 'the' (say, % index 60) appears in the email, then x(60) = 1. The feature % vector should look like: % % x = [ 0 0 0 0 1 0 0 0 ... 0 0 0 0 1 ... 0 0 0 1 0 ..]; % % % ========================================================================= end