title: Evaluate sympy expression from an array of values
body: <p>I'm experimenting with sympy and I've hit upon an issue I can't work out.</p>
  
  <p>Using scipy I can write an expression and evaluate it for an array of x values as follows:</p>
  
  <pre><code>import scipy
  xvals = scipy.arange(-100,100,0.1)
  f = lambda x: x**2
  f(xvals)
  </code></pre>
  
  <p>Using sympy I can write the same expression as follows:</p>
  
  <pre><code>import sympy
  x = sympy.symbols('x')
  g = x**2
  </code></pre>
  
  <p>I can evaluate this expression for a single value by doing the following:</p>
  
  <pre><code>g.evalf(subs={x:10})
  </code></pre>
  
  <p>However I can't work out how to evaluate it for an array of x values, like I did with scipy. How would I do this?</p>