我看到有一个array_split
和split
methods,但是当您必须分割一个长度不是数组大小整数倍的数组时,它们不是很方便。而且,这些方法输入的是切片数而不是切片大小。我需要更类似于Matlab的buffer方法的方法,该方法更适合信号处理。
例如,如果我想将信号缓冲到大小为60的块中,则需要做:np.vstack(np.hsplit(x.iloc[0:((len(x)//60)*60)], len(x)//60))
麻烦。
最佳答案
我编写了以下例程来处理所需的用例,但尚未对“underlap”进行实现/测试。
请随时提出改进建议。
def buffer(X, n, p=0, opt=None):
'''Mimic MATLAB routine to generate buffer array
MATLAB docs here: https://se.mathworks.com/help/signal/ref/buffer.html
Parameters
----------
x: ndarray
Signal array
n: int
Number of data segments
p: int
Number of values to overlap
opt: str
Initial condition options. default sets the first `p` values to zero,
while 'nodelay' begins filling the buffer immediately.
Returns
-------
result : (n,n) ndarray
Buffer array created from X
'''
import numpy as np
if opt not in [None, 'nodelay']:
raise ValueError('{} not implemented'.format(opt))
i = 0
first_iter = True
while i < len(X):
if first_iter:
if opt == 'nodelay':
# No zeros at array start
result = X[:n]
i = n
else:
# Start with `p` zeros
result = np.hstack([np.zeros(p), X[:n-p]])
i = n-p
# Make 2D array and pivot
result = np.expand_dims(result, axis=0).T
first_iter = False
continue
# Create next column, add `p` results from last col if given
col = X[i:i+(n-p)]
if p != 0:
col = np.hstack([result[:,-1][-p:], col])
i += n-p
# Append zeros if last row and not length `n`
if len(col) < n:
col = np.hstack([col, np.zeros(n-len(col))])
# Combine result with next row
result = np.hstack([result, np.expand_dims(col, axis=0).T])
return result