Convert a list of string into a vector : <p>Given:</p>

<p><code>['1 -1 1 1 1 1 1 1 1']</code></p>

<p>How can I convert it (efficiently) to be a vector of integers something like:</p>

<p><code>[1 -1 1 1 1 1 1 1 1]</code></p>

<p>Thank you.</p>
