Python 访问熊猫数据帧索引时出错
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error when accessing pandas dataframe index
提问by Mohamed Ali JAMAOUI
I get an error when trying to access a single element in a pandas dataframe this way test_df["LABEL"][0]. Here is a code snippet on how I am loading the data:
尝试以这种方式 test_df["LABEL"][0] 访问 Pandas 数据帧中的单个元素时出现错误。这是关于我如何加载数据的代码片段：
print "reading test set"
test_set = pd.read_csv(data_path+"small_test_products.txt", header=0, delimiter="|")
print "shape of the test set", test_set.shape
test_df = pd.DataFrame(test_set)
lengthOfTestSet = len(test_df["LABEL"])
print test_df["LABEL"][0]
Here is the error I am getting:
这是我得到的错误：
File "code.py", line 80, in print test_df["LABEL"][0] File "/usr/local/lib/python2.7/dist-packages/pandas/core/series.py", line 521, in getitemresult = self.index.get_value(self, key) File "/usr/local/lib/python2.7/dist-packages/pandas/core/index.py", line 3562, in get_value loc = self.get_loc(k) File "/usr/local/lib/python2.7/dist-packages/pandas/core/index.py", line 3619, in get_loc return super(Float64Index, self).get_loc(key, method=method) File "/usr/local/lib/python2.7/dist-packages/pandas/core/index.py", line 1572, in get_loc return self._engine.get_loc(_values_from_object(key)) File "pandas/index.pyx", line 134, in pandas.index.IndexEngine.get_loc (pandas/index.c:3824) File "pandas/index.pyx", line 154, in pandas.index.IndexEngine.get_loc (pandas/index.c:3704) File "pandas/hashtable.pyx", line 541, in pandas.hashtable.Float64HashTable.get_item (pandas/hashtable.c:9914)
File "pandas/hashtable.pyx", line 547, in pandas.hashtable.Float64HashTable.get_item (pandas/hashtable.c:9852) KeyError: 0.0
文件“code.py”，第 80 行，打印 test_df[“LABEL”][0] 文件“/usr/local/lib/python2.7/dist-packages/pandas/core/series.py”，第 521 行，在getitem中结果 = self.index.get_value(self, key) 文件“/usr/local/lib/python2.7/dist-packages/pandas/core/index.py”，第 3562 行，在 get_value loc = self.get_loc(k ) 文件“/usr/local/lib/python2.7/dist-packages/pandas/core/index.py”，第 3619 行，在 get_loc 中返回 super(Float64Index, self).get_loc(key, method=method) 文件“ /usr/local/lib/python2.7/dist-packages/pandas/core/index.py”，第 1572 行，在 get_loc 中返回 self._engine.get_loc(_values_from_object(key)) 文件“pandas/index.pyx”，第 134 行，pandas.index.IndexEngine.get_loc (pandas/index.c:3824) 文件“pandas/index.pyx”，第 154 行，pandas.index.IndexEngine.get_loc (pandas/index.c:3704) 文件“pandas/hashtable.pyx”，第 541 行，在 pandas.hashtable.Float64HashTable.get_item (pandas/hashtable.c:9914)
文件“pandas/hashtable.pyx”，第 547 行，在 pandas.hashtable.Float64HashTable.get_item (pandas/hashtable.c:9852) KeyError: 0.0
What am I missing?
我错过了什么？
采纳答案by Seth
Like EdChum said 0 is probably not in your index.
就像 EdChum 说的 0 可能不在您的索引中。
Try: df.iloc[0]or df['label'].iloc[0], which is integer based location.
尝试：df.iloc[0]or df['label'].iloc[0]，这是基于整数的位置。
To reset the index if you are having trouble with that: df.reset_index(drop=True)
如果遇到问题，要重置索引： df.reset_index(drop=True)
Check out panda's indexing docfor more information on it
查看熊猫的索引文档以获取更多信息
