这是一个带有^{}-# https://stackoverflow.com/a/52718782/ @Divakar

def maxisland_start_len_mask(a, fillna_index = -1, fillna_len = 0):

# a is a boolean array

pad = np.zeros(a.shape[1],dtype=bool)

mask = np.vstack((pad, a, pad))

mask_step = mask[1:] != mask[:-1]

idx = np.flatnonzero(mask_step.T)

island_starts = idx[::2]

island_lens = idx[1::2] - idx[::2]

n_islands_percol = mask_step.sum(0)//2

bins = np.repeat(np.arange(a.shape[1]),n_islands_percol)

scale = island_lens.max()+1

scaled_idx = np.argsort(scale*bins + island_lens)

grp_shift_idx = np.r_[0,n_islands_percol.cumsum()]

max_island_starts = island_starts[scaled_idx[grp_shift_idx[1:]-1]]

max_island_percol_start = max_island_starts%(a.shape[0]+1)

valid = n_islands_percol!=0

cut_idx = grp_shift_idx[:-1][valid]

max_island_percol_len = np.maximum.reduceat(island_lens, cut_idx)

out_len = np.full(a.shape[1], fillna_len, dtype=int)

out_len[valid] = max_island_percol_len

out_index = np.where(valid,max_island_percol_start,fillna_index)

return out_index, out_len

def maxisland_start_len(a, trigger_val, comp_func=np.greater):

# a is 2D array as the data

mask = comp_func(a,trigger_val)

return maxisland_start_len_mask(mask, fillna_index = -1, fillna_len = 0)

样本运行-

^{pr2}$