熊貓減去從列表值的組平均值

Question

所以我有一個基因芯片的數據集，其中16芯片測量1組織樣本。我想從每個芯片中的每個基因中減去所有芯片上該基因的平均值。所以我按基因分組並計算平均值。現在我想獲取原始PM強度值並從該基因中減去平均值。 因此，我需要將基因列與表中存儲此基因組平均值的索引匹配，然後從PM列中減去此值。

totalgene = genedata.groupby(genedata['GENE']).mean()[['PM','LOGPM']] 

genedata['MEANNORM'] = genedata['PM'] - totalgene.ix[genedata['GENE']]['AVGPM'] 
genedata['MEANNORM'] = genedata['LOGPM'] - totalgene.ix[genedata['GENE']]['AVGLOGPM'] 

導致錯誤：

--------------------------------------------------------------------------- 
ValueError        Traceback (most recent call last) 
<ipython-input-18-08c1bb979f9c> in <module>() 
----> 1 genedata['MEANNORM'] = genedata['PM'] - totalgene.ix[genedata['GENE'],'AVGPM'] 
     2 genedata['MEANNORM'] = genedata['LOGPM'] - totalgene.ix[genedata['GENE'],'AVGLOGPM'] 

C:\Users\timothy\Anaconda3\lib\site-packages\pandas\core\frame.py in __setitem__(self, key, value) 
    2417   else: 
    2418    # set column 
-> 2419    self._set_item(key, value) 
    2420 
    2421  def _setitem_slice(self, key, value): 

C:\Users\timothy\Anaconda3\lib\site-packages\pandas\core\frame.py in _set_item(self, key, value) 
    2483 
    2484   self._ensure_valid_index(value) 
-> 2485   value = self._sanitize_column(key, value) 
    2486   NDFrame._set_item(self, key, value) 
    2487 

C:\Users\timothy\Anaconda3\lib\site-packages\pandas\core\frame.py in _sanitize_column(self, key, value, broadcast) 
    2633 
    2634   if isinstance(value, Series): 
-> 2635    value = reindexer(value) 
    2636 
    2637   elif isinstance(value, DataFrame): 

C:\Users\timothy\Anaconda3\lib\site-packages\pandas\core\frame.py in reindexer(value) 
    2625      # duplicate axis 
    2626      if not value.index.is_unique: 
-> 2627       raise e 
    2628 
    2629      # other 

C:\Users\timothy\Anaconda3\lib\site-packages\pandas\core\frame.py in reindexer(value) 
    2620     # GH 4107 
    2621     try: 
-> 2622      value = value.reindex(self.index)._values 
    2623     except Exception as e: 
    2624 

C:\Users\timothy\Anaconda3\lib\site-packages\pandas\core\series.py in reindex(self, index, **kwargs) 
    2360  @Appender(generic._shared_docs['reindex'] % _shared_doc_kwargs) 
    2361  def reindex(self, index=None, **kwargs): 
-> 2362   return super(Series, self).reindex(index=index, **kwargs) 
    2363 
    2364  @Appender(generic._shared_docs['fillna'] % _shared_doc_kwargs) 

C:\Users\timothy\Anaconda3\lib\site-packages\pandas\core\generic.py in reindex(self, *args, **kwargs) 
    2257   # perform the reindex on the axes 
    2258   return self._reindex_axes(axes, level, limit, tolerance, method, 
-> 2259         fill_value, copy).__finalize__(self) 
    2260 
    2261  def _reindex_axes(self, axes, level, limit, tolerance, method, fill_value, 

C:\Users\timothy\Anaconda3\lib\site-packages\pandas\core\generic.py in _reindex_axes(self, axes, level, limit, tolerance, method, fill_value, copy) 
    2275    obj = obj._reindex_with_indexers({axis: [new_index, indexer]}, 
    2276            fill_value=fill_value, 
-> 2277            copy=copy, allow_dups=False) 
    2278 
    2279   return obj 

C:\Users\timothy\Anaconda3\lib\site-packages\pandas\core\generic.py in _reindex_with_indexers(self, reindexers, fill_value, copy, allow_dups) 
    2369             fill_value=fill_value, 
    2370             allow_dups=allow_dups, 
-> 2371             copy=copy) 
    2372 
    2373   if copy and new_data is self._data: 

C:\Users\timothy\Anaconda3\lib\site-packages\pandas\core\internals.py in reindex_indexer(self, new_axis, indexer, axis, fill_value, allow_dups, copy) 
    3837   # some axes don't allow reindexing with dups 
    3838   if not allow_dups: 
-> 3839    self.axes[axis]._can_reindex(indexer) 
    3840 
    3841   if axis >= self.ndim: 

C:\Users\timothy\Anaconda3\lib\site-packages\pandas\indexes\base.py in _can_reindex(self, indexer) 
    2492   # trying to reindex on an axis with duplicates 
    2493   if not self.is_unique and len(indexer): 
-> 2494    raise ValueError("cannot reindex from a duplicate axis") 
    2495 
    2496  def reindex(self, target, method=None, level=None, limit=None, 

ValueError: cannot reindex from a duplicate axis 

，我不知道爲什麼？ 有人可以幫忙嗎？

Answer 1

考慮transform了一種直列骨料它返回一個系列，可以從原始列中減去，PM和LOGPM：

genedata['MEANNORM_PM'] = genedata['PM'] - \ 
          genedata.groupby(['GENE'])['PM'].transform('mean') 

genedata['MEANNORM_LOGPM'] = genedata['LOGPM'] - \ 
           genedata.groupby(['GENE'])['LOGPM'].transform('mean')