Python 把尾随的1放在那里。我可能不得不改变解决方案中的一些东西。那么,再次尝试理解这个问题,假设mask=[1,0,0,0,0,1,1,0,0,0,0,1,0],那么输出必须是什么呢?那将是[1,0,0,0,0,0,1,1,0,0,0,0,0,0,0,1,1]。
Python 把尾随的1放在那里。我可能不得不改变解决方案中的一些东西。那么,再次尝试理解这个问题,假设mask=[1,0,0,0,0,1,1,0,0,0,0,1,0],那么输出必须是什么呢?那将是[1,0,0,0,0,0,1,1,0,0,0,0,0,0,0,1,1]。,python,arrays,numpy,Python,Arrays,Numpy,把尾随的1放在那里。我可能不得不改变解决方案中的一些东西。那么,再次尝试理解这个问题,假设mask=[1,0,0,0,0,1,1,0,0,0,0,1,0],那么输出必须是什么呢?那将是[1,0,0,0,0,0,1,1,0,0,0,0,0,0,0,1,1]。如果阈值为2、3或4,因此要求至少2、3或4个连续零才能保持不变。@LukasBrunner和if mask=[0,0,1,0,0,0,0,0,0,1,1,0,0,0,1,0,0],这与问题中列出的输入相同,但是,如果在开始处有两个额外的零,并
把尾随的
1
放在那里。我可能不得不改变解决方案中的一些东西。那么,再次尝试理解这个问题,假设mask=[1,0,0,0,0,1,1,0,0,0,0,1,0]
,那么输出必须是什么呢?那将是[1,0,0,0,0,0,1,1,0,0,0,0,0,0,0,1,1]
。如果阈值
为2、3或4,因此要求至少2、3或4个连续零才能保持不变。@LukasBrunner和if mask=[0,0,1,0,0,0,0,0,0,1,1,0,0,0,1,0,0]
,这与问题中列出的输入相同,但是,如果在开始处有两个额外的零,并且再次假设阈值=3
,那么输出必须是什么?那将是[1,1,1,0,0,0,1,1,1,1]
。
new_mask = find_consecutive(mask, threshold=3)
mask[:, i_lon, i_lat]
# [1, 0, 0, 0, 0, 1, 1, 0, 0, 1, 0]
new_mask[:, i_lon, i_lat]
# [1, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1]
from scipy.ndimage import measurements
structure = np.zeros((3, 3, 3))
structure[:, 1, 1] = 1
labels, nr_labels = measurements.label(1 - mask, structure=structure)
_, counts = np.unique(labels, return_counts=True)
labels_selected = [i_count for i_count, count in enumerate(counts)
if count >= threshold]
from scipy.ndimage import binary_closing
out = mask | binary_closing(mask, structure=np.ones(threshold))
def numpy_binary_closing(mask,threshold):
# Define kernel
K = np.ones(threshold)
# Perform dilation and threshold at 1
dil = np.convolve(mask,K,mode='same')>=1
# Perform erosion on the dilated mask array and threshold at given threshold
dil_erd = np.convolve(dil,K,mode='same')>= threshold
return dil_erd
In [133]: mask
Out[133]:
array([ True, False, False, False, False, True, True, False, False,
True, False], dtype=bool)
In [134]: threshold = 3
In [135]: binary_closing(mask, structure=np.ones(threshold))
Out[135]:
array([False, False, False, False, False, True, True, True, True,
True, False], dtype=bool)
In [136]: numpy_binary_closing(mask,threshold)
Out[136]:
array([False, False, False, False, False, True, True, True, True,
True, False], dtype=bool)
In [137]: mask | binary_closing(mask, structure=np.ones(threshold))
Out[137]:
array([ True, False, False, False, False, True, True, True, True,
True, False], dtype=bool)
In [138]: mask| numpy_binary_closing(mask,threshold)
Out[138]:
array([ True, False, False, False, False, True, True, True, True,
True, False], dtype=bool)
In [163]: mask = np.random.rand(10000) > 0.5
In [164]: threshold = 3
In [165]: %timeit binary_closing(mask, structure=np.ones(threshold))
1000 loops, best of 3: 582 µs per loop
In [166]: %timeit numpy_binary_closing(mask,threshold)
10000 loops, best of 3: 178 µs per loop
In [167]: out1 = binary_closing(mask, structure=np.ones(threshold))
In [168]: out2 = numpy_binary_closing(mask,threshold)
In [169]: np.allclose(out1,out2) # Verify outputs
Out[169]: True
In [176]: mask = np.random.rand(10000) > 0.8
In [177]: threshold = 11
In [178]: %timeit binary_closing(mask, structure=np.ones(threshold))
1000 loops, best of 3: 823 µs per loop
In [179]: %timeit numpy_binary_closing(mask,threshold)
1000 loops, best of 3: 331 µs per loop
In [180]: out1 = binary_closing(mask, structure=np.ones(threshold))
In [181]: out2 = numpy_binary_closing(mask,threshold)
In [182]: np.allclose(out1,out2) # Verify outputs
Out[182]: True
mask_ext = np.pad(mask,1,'constant',constant_values=(1))
out = mask_ext | binary_closing(mask_ext, structure=np.ones(threshold))
out = out[1:-1]
In [369]: mask
Out[369]:
array([False, False, True, False, False, False, False, True, True,
False, False, True, False], dtype=bool)
In [370]: threshold = 3
In [371]: mask_ext = np.pad(mask,1,'constant',constant_values=(1))
...: out = mask_ext | binary_closing(mask_ext, structure=np.ones(threshold))
...: out = out[1:-1]
...:
In [372]: out
Out[372]:
array([ True, True, True, False, False, False, False, True, True,
True, True, True, True], dtype=bool)
import numpy as np
from scipy.ndimage import measurements
def select_consecutive(mask, threshold):
structure = np.zeros((3, 3, 3))
structure[:, 1, 1] = 1
labels, _ = measurements.label(1 - mask, structure=structure)
# find positions of all unmasked values
# object_slices = measurements.find_objects(labels)
_, counts = np.unique(labels, return_counts=True)
labels_selected = [i_count for i_count, count in enumerate(counts)
if count >= threshold and i_count != 0]
ind = np.in1d(labels.flatten(), labels_selected).reshape(mask.shape)
mask_new = np.ones_like(mask)
mask_new[ind] = 0
return mask_new