我们从Python开源项目中，提取了以下6个代码示例，用于说明如何使用numpy.ma.concatenate()。
def find_duplicates(a, key=None, ignoremask=True, return_index=False): """ Find the duplicates in a structured array along a given key Parameters ---------- a : array-like Input array key : {string, None}, optional Name of the fields along which to check the duplicates. If None, the search is performed by records ignoremask : {True, False}, optional Whether masked data should be discarded or considered as duplicates. return_index : {False, True}, optional Whether to return the indices of the duplicated values. Examples -------- >>> from numpy.lib import recfunctions as rfn >>> ndtype = [('a', int)] >>> a = np.ma.array([1, 1, 1, 2, 2, 3, 3], ... mask=[0, 0, 1, 0, 0, 0, 1]).view(ndtype) >>> rfn.find_duplicates(a, ignoremask=True, return_index=True) ... # XXX: judging by the output, the ignoremask flag has no effect """ a = np.asanyarray(a).ravel() # Get a dictionary of fields fields = get_fieldstructure(a.dtype) # Get the sorting data (by selecting the corresponding field) base = a if key: for f in fields[key]: base = base[f] base = base[key] # Get the sorting indices and the sorted data sortidx = base.argsort() sortedbase = base[sortidx] sorteddata = sortedbase.filled() # Compare the sorting data flag = (sorteddata[:-1] == sorteddata[1:]) # If masked data must be ignored, set the flag to false where needed if ignoremask: sortedmask = sortedbase.recordmask flag[sortedmask[1:]] = False flag = np.concatenate(([False], flag)) # We need to take the point on the left as well (else we're missing it) flag[:-1] = flag[:-1] + flag[1:] duplicates = a[sortidx][flag] if return_index: return (duplicates, sortidx[flag]) else: return duplicates
