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);

    % ====================== 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 ..];
    %
    x(word_indices) = 1;
end
