To remove NaN values from a NumPy array x:
x = x[~numpy.isnan(x)]
Explanation
The inner function numpy.isnan returns a boolean/logical array which has the value True everywhere that x is not-a-number. Since we want the opposite, we use the logical-not operator ~ to get an array with Trues everywhere that x is a valid number.
Lastly, we use this logical array to index into the original array x, in order to retrieve just the non-NaN values.