ValueError: Expected 2D array, got 1D array instead
selector.fit(X_rnd.reshape,Y_rnd) #select best features

X_rnd should be a 2D matrix.

I believe this error came when "fit" method was executed with X_rnd
but your code is showing X_rnd.reshape. In this case, error should be -

    ValueError: Expected 2D array, got scalar array instead:
    array=&lt;built-in method reshape of numpy.ndarray object at 0x000000000C28EAD0&gt;.
    Reshape your data either using array.reshape(-1, 1) if your data has a single                         feature or array.reshape(1, -1) if it contains a single sample.