<p dir="auto">You need to double-transpose vectors to make them into 1-column matrices so that<br>
you can add them to 1-column matrices or multiply them with one-row matrices (on<br>
either side).</p>
<div class="snippet-clipboard-content notranslate position-relative overflow-auto" data-snippet-clipboard-copy-content="julia&gt; X = [ i^2 - j | i=1:10, j=1:10 ];

julia&gt; typeof(X)
Array{Int64,2}

julia&gt; X[:,1]
10x1 Int64 Array
0 
3 
8 
15 
24 
35 
48 
63 
80 
99 "><pre class="notranslate"><code class="notranslate">julia&gt; X = [ i^2 - j | i=1:10, j=1:10 ];

julia&gt; typeof(X)
Array{Int64,2}

julia&gt; X[:,1]
10x1 Int64 Array
0 
3 
8 
15 
24 
35 
48 
63 
80 
99 
</code></pre></div>