Using flow_from_dataframe what is the correct “value” for y_col

问题

I am reading in a csv file with pandas, and give the column names stored in colname

colnames=['file', 'label'] 
# Read data from file 
data = pd.read_csv('./Hand_Annotations_2.csv',names=colnames, header=None)
# Preview the first 5 lines of the loaded data 
data.head()

Then, I use ImageDataGenerator() and flow_fromdataframe() to get batches of data

train_generator=datagen.flow_from_dataframe(dataframe=data,
                                            directory=None, 
                                            x_col=colnames[0], 
                                            y_col=colnames[1],
                                            class_indices=IDmap,
                                            class_mode="categorical", target_size=(224,224), batch_size=32)

But I get an error, as below:

TypeError: If class_mode="categorical", y_col="label" column values must be type string, list or tuple.

But my y_col is a string. I get the same error if I just enter "label". It also seems to work with x_col.

Can someone point me to my mistake?

Thanks

---

Solution

read csv with dtype e.g. str:

data = pd.read_csv('./Hand_Annotations_2.csv',dtype=str,names=colnames, header=None)

回答1:

You can check the code in github for what it is actually being checked, specially here. Keras preprocessing is checking that all the values have allowed types (str, list or tuple), so the check is failing, you have to check that all values of the y_col column have the right type.

来源：https://stackoverflow.com/questions/56460581/using-flow-from-dataframe-what-is-the-correct-value-for-y-col