Resample a numpy array

Question

It\'s easy to resample an array like

 a = numpy.array([1,2,3,4,5,6,7,8,9,10])

with an integer resampling factor. For instance, wi

Answer 1

In signal processing, you can think of resampling as basically rescaling the array and interpolating the missing values or values with non-integer index using nearest, linear, cubic, etc methods.

Using scipy.interpolate.interp1d, you can achieve one dimensional resampling using the following function

def resample(x, factor, kind='linear'):
    n = np.ceil(x.size / factor)
    f = interp1d(np.linspace(0, 1, x.size), x, kind)
    return f(np.linspace(0, 1, n))

e.g.:

a = np.array([1,2,3,4,5,6,7,8,9,10])
resample(a, factor=1.5, kind='linear')

yields

array([ 1. ,  2.5,  4. ,  5.5,  7. ,  8.5, 10. ])

and

a = np.array([1,2,3,4,5,6,7,8,9,10])
resample(a, factor=1.5, kind='nearest')

yields

array([ 1.,  2.,  4.,  5.,  7.,  8., 10.])