python if语句字典与Series不兼容的索引器

这个脚本：

for x in df.index: 
    if df.loc[x,'medicament1'] in dicoprix:
        df.loc[x,'coutmed1'] = dicoprix[df.loc[x,'medicament1']]

给出这个错误：

File "<ipython-input-35-097fdb2220b8>", line 3, in <module>
    df.loc[x,'coutmed1'] = dicoprix[df.loc[x,'medicament1']]

  File "//anaconda/lib/python2.7/site-packages/pandas/core/indexing.py", line 115, in __setitem__
    self._setitem_with_indexer(indexer, value)

  File "//anaconda/lib/python2.7/site-packages/pandas/core/indexing.py", line 346, in _setitem_with_indexer
    value = self._align_series(indexer, value)

  File "//anaconda/lib/python2.7/site-packages/pandas/core/indexing.py", line 613, in _align_series
    raise ValueError('Incompatible indexer with Series')

ValueError: Incompatible indexer with Series

但脚本正在运行，这意味着df.loc[x,'coutmed1']取我想要的值。

我不明白我做错了什么？

我认为问题出自于此

dicoprix[df.loc[x,'medicament1']]

当字典中的一个键引用多个值时，就会出现此问题！