我有一個(gè)CSV文件，其中幾行n/a。當(dāng)我將其加載為pandas數(shù)據(jù)框時(shí)，顯示為nan。當(dāng)我使用類似功能這會(huì)導(dǎo)致問題split，lower等這些幾行。data_df['column'][104]>>> nandata_df['column'][104].split()>>> AttributeError                            Traceback (most recent call last)<ipython-input-38-6efe06f0a4ec> in <module>()----> 1 data_df['column'][104].split()AttributeError: 'float' object has no attribute 'split'data_df['column'][104].lower()>>>AttributeError                            Traceback (most recent call last)<ipython-input-41-c80cc9ae0712> in <module>()----> 1 data_df['column'][104].lower()AttributeError: 'float' object has no attribute 'lower'當(dāng)我嘗試nan用空格替換s（不會(huì)導(dǎo)致這些錯(cuò)誤）時(shí)，使用該fillna方法不會(huì)執(zhí)行任何操作：data_df.fillna('')data_df['column'][104]>>> nan所以我嘗試將其替換為字符串：for i in range(len(data_df)):    if data_df['column'][i]=='nan':        data_df['column'][i]=''data_df['column'][104]>>> nanfor i in range(len(data_df)):    if data_df['column'][i]=='n/a':        data_df['column'][i]=''data_df['column'][104]>>> nan以下內(nèi)容不打印任何內(nèi)容：for i in range(len(data_df)):    if (data_df['column'][i]=='nan' or data_df['column'][i]=='n/a'):        print(data_df['column'][i])為什么我無法捕捉和替換nans或n/as？以及我該如何解決？