我的以下代码如下：
train_generator = aug.flow_from_dataframe(dataframe = z1,
directory = None,
x_col = 'id',
y_col = 'label',
class_mode = 'categorical',
target_size = (mysize, mysize),
shuffle = True,
batch_size = mybatch,
seed = 40)
val_datagen = ImageDataGenerator(rescale = 1./255)
val_generator = val_datagen.flow_from_dataframe(z2,
x_col = 'id',
y_col = 'label',
class_mode = 'categorical',
target_size = (mysize, mysize),
batch_size = mybatch,
seed = 41)
test_datagen = ImageDataGenerator(rescale = 1./255)
test_generator = test_datagen.flow_from_dataframe(testfiles,
x_col = 'id',
directory = None,
color_mode = 'rgb',
target_size = (mysize, mysize),
batch_size = 1,
class_mode = None,
shuffle = False,
seed = 42)
我已检查，并且我的DataFrames z1，z2和testfiles中都有一列，标记为id。这是其中每个的head()：
z1.head()
Output:
label id
0 0.0 train/cat.5077.jpg
1 0.0 train/cat.2718.jpg
2 0.0 train/cat.10151.jpg
3 0.0 train/cat.3406.jpg
4 0.0 train/cat.4369.jpg
z2.head()
Output:
label id
6 0.0 train/cat.8553.jpg
7 0.0 train/cat.9895.jpg
9 0.0 train/cat.6218.jpg
11 0.0 train/cat.12020.jpg
17 0.0 train/cat.10637.jpg
testfiles.head()
Output:
id
[testfiles是一个空的DataFrame，但它确实包含名称为id的列。
所以我得到一个KeyError，这很混乱，它显示如下：
---------------------------------------------------------------------------
KeyError Traceback (most recent call last)
//anaconda3/lib/python3.7/site-packages/pandas/core/indexes/base.py in get_loc(self, key, method, tolerance)
2656 try:
-> 2657 return self._engine.get_loc(key)
2658 except KeyError:
pandas/_libs/index.pyx in pandas._libs.index.IndexEngine.get_loc()
pandas/_libs/index.pyx in pandas._libs.index.IndexEngine.get_loc()
pandas/_libs/hashtable_class_helper.pxi in pandas._libs.hashtable.PyObjectHashTable.get_item()
pandas/_libs/hashtable_class_helper.pxi in pandas._libs.hashtable.PyObjectHashTable.get_item()
KeyError: 'id'
During handling of the above exception, another exception occurred:
KeyError Traceback (most recent call last)
<ipython-input-15-2a56a9e3c4bf> in <module>
40 class_mode = None,
41 shuffle = False,
---> 42 seed = 42)
//anaconda3/lib/python3.7/site-packages/keras/preprocessing/image.py in flow_from_dataframe(self, dataframe, directory, x_col, y_col, weight_col, target_size, color_mode, classes, class_mode, batch_size, shuffle, seed, save_to_dir, save_prefix, save_format, subset, interpolation, validate_filenames, **kwargs)
592 interpolation=interpolation,
593 validate_filenames=validate_filenames,
--> 594 **kwargs
595 )
596
//anaconda3/lib/python3.7/site-packages/keras/preprocessing/image.py in __init__(self, dataframe, directory, image_data_generator, x_col, y_col, weight_col, target_size, color_mode, classes, class_mode, batch_size, shuffle, seed, data_format, save_to_dir, save_prefix, save_format, subset, interpolation, dtype, validate_filenames)
233 interpolation=interpolation,
234 dtype=dtype,
--> 235 validate_filenames=validate_filenames)
236
237
//anaconda3/lib/python3.7/site-packages/keras_preprocessing/image/dataframe_iterator.py in __init__(self, dataframe, directory, image_data_generator, x_col, y_col, weight_col, target_size, color_mode, classes, class_mode, batch_size, shuffle, seed, data_format, save_to_dir, save_prefix, save_format, subset, interpolation, dtype, validate_filenames)
144 if class_mode not in ["input", "multi_output", "raw", None]:
145 self.classes = self.get_classes(df, y_col)
--> 146 self.filenames = df[x_col].tolist()
147 self._sample_weight = df[weight_col].values if weight_col else None
148
//anaconda3/lib/python3.7/site-packages/pandas/core/frame.py in __getitem__(self, key)
2925 if self.columns.nlevels > 1:
2926 return self._getitem_multilevel(key)
-> 2927 indexer = self.columns.get_loc(key)
2928 if is_integer(indexer):
2929 indexer = [indexer]
//anaconda3/lib/python3.7/site-packages/pandas/core/indexes/base.py in get_loc(self, key, method, tolerance)
2657 return self._engine.get_loc(key)
2658 except KeyError:
-> 2659 return self._engine.get_loc(self._maybe_cast_indexer(key))
2660 indexer = self.get_indexer([key], method=method, tolerance=tolerance)
2661 if indexer.ndim > 1 or indexer.size > 1:
pandas/_libs/index.pyx in pandas._libs.index.IndexEngine.get_loc()
pandas/_libs/index.pyx in pandas._libs.index.IndexEngine.get_loc()
pandas/_libs/hashtable_class_helper.pxi in pandas._libs.hashtable.PyObjectHashTable.get_item()
pandas/_libs/hashtable_class_helper.pxi in pandas._libs.hashtable.PyObjectHashTable.get_item()
KeyError: 'id'
有人知道这里发生了什么吗？据我了解，KeyError是在引用字典中不包含的值（即不存在的列）时发生的。
据我了解，另一个post中引用了类似的问题，但似乎没有解决：
[图像数据生成器首先验证您的[[DataFrame中的文件是否全部存在，如果没有要验证的内容，则提高Key error。
# get labels for each observation
if class_mode not in ["input", "multi_output", "raw", None]:
self.classes = self.get_classes(df, y_col)
self.filenames = df[x_col].tolist() <<< ERROR HERE
self._sample_weight = df[weight_col].values if weight_col else None
此DataFrame转换
df中包含的所有值都转换为列表。因此，如果您进一步挖掘。if self.columns.nlevels > 1:
return self._getitem_multilevel(key)
indexer = self.columns.get_loc(key) <<< ERROR HERE
if is_integer(indexer):
indexer = [indexer]
您可以看到该行，即，这意味着当您将其送入空数组时将无用。为此，您可以尝试使用空字符串key中的column是用于引用的索引。保证传递空数组[]都会引发错误，因为您将使用Nothing作为参考。而且，图像数据生成器仅
返回值
testfiles = pd.DataFrame([''], columns = ['id'])创建一个DataFrame以避免遇到Key Error。