scipy.fftpack provides fft function to calculate Discrete Fourier Transform on an array. In this tutorial, we shall learn the syntax and the usage of fft function with SciPy FFT Examples.


y = scipy.fftpack.fft(x, n=None, axis=-1, overwrite_x=False)
Parameter Required/ Optional [datatype] Description
xRequired[array] Array on which FFT has to be calculated.
nOptional[int] Length of the Fourier transform. If n < x.shape[axis], x is truncated. If n > x.shape[axis], x is zero-padded. The default results in n = x.shape[axis].
axisOptional[int] Axis along which the fft’s are computed; the default is over the last axis (i.e., axis=-1).
overwrite_xOptional[boolean] If True, the contents of x can be destroyed; the default is False.
y[Returned value][complex ndarray] Discrete Fourier Transform of x.

Values provided for the optional arguments are default values.

Example 1 – SciPy FFT

# import numpy
import numpy as np

# import fft
from scipy.fftpack import fft

# numpy array
x = np.array([1.0, 2.0, 1.0, 2.0, -1.0])
print("x            : ",x)

# apply fft function on array
y = fft(x)
print("fft(x)       : ",y)
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x            :  [ 1.  2.  1.  2. -1.]
fft(x)       :  [ 5.00000000+0.j         -1.11803399-2.2653843j   1.11803399-2.71441227j
  1.11803399+2.71441227j -1.11803399+2.2653843j ]