问题
What I want is to extend an array of length m to an array of length n (n>m), and interpolate the missing values linearly.
For example, I want to extend this array [1,5,1,7] to an array of length 7, the result should be [1,3,5,3,1,5,7], where the bold figures result from linear interpolation.
Is there an easy way to do this in Python? Thanks in advance.
回答1:
The interp function from numpy can do what you want.
Example:
>>> xp = [1, 2, 3]
>>> fp = [3, 2, 0]
>>> np.interp(2.5, xp, fp)
1.0
>>> np.interp([0, 1, 1.5, 2.72, 3.14], xp, fp)
array([ 3. , 3. , 2.5 , 0.56, 0. ])
回答2:
use extend :
a = [1, 2, 3]
a.extend([4, 5])
print (a)
output:
[1, 2, 3, 4, 5]
you will have to use your own logic for the input array for extend
回答3:
To interleave two lists, you could use:
In [240]: x = [1, 5, 1, 7]
In [241]: y = [3, 3, 5]
In [242]: from itertools import chain, izip
In [243]: list(chain.from_iterable(izip(x, y)))
Out[243]: [1, 3, 5, 3, 1, 5]
as you see above it would stop at the shorter list. Check this answer for overcoming this limitation.
来源：https://stackoverflow.com/questions/30023326/how-to-extend-an-array-with-linear-interpolation