python – AttributeError：’Series’对象没有属性’notna’

我有一个csv文件,其中包含多个包含空字符串的列.在将csv读入pandas数据帧后,空字符串将转换为NaN.

现在我想将一个字符串标签附加到已经存在于列中的字符串,但仅添加到其中包含某些值的字符串而不是那些具有NaN的字符串

这就是我想要做的：

with open('file1.csv','r') as file:
    for chunk in pd.read_csv(file,chunksize=1000, header=0, names=['A','B','C','D'])
        if len(chunk) >=1:
            if chunk['A'].notna:
                chunk['A'] = "tag-"+chunk['A'].astype(str)
            if chunk['B'].notna:
                chunk['B'] = "tag-"+chunk['B'].astype(str)
            if chunk['C'].notna:
                chunk['C'] = "tag-"+chunk['C'].astype(str)
            if chunk['D'].notna:
                chunk['D'] = "tag-"+chunk['D'].astype(str)

这是我得到的错误：

AttributeError: 'Series' object has no attribute 'notna'

我想要的最终输出应该是这样的：

A,B,C,D
tag-a,tab-b,tag-c,
tag-a,tag-b,,
tag-a,,,
,,tag-c,
,,,tag-d
,tag-b,,tag-d

解决方法:

我相信你需要mask为所有列添加标签：

for chunk in pd.read_csv('file1.csv',chunksize=2, header=0, names=['A','B','C','D']):
    if len(chunk) >=1:
        m1 = chunk.notna()
        chunk = chunk.mask(m1, "tag-" + chunk.astype(str))

您需要升级到最新版本的pandas,0.21.0.

你可以查看docs：

In order to promote more consistency among the pandas API, we have added additional top-level functions isna() and notna() that are aliases for isnull() and notnull(). The naming scheme is now more consistent with methods like .dropna() and .fillna(). Furthermore in all cases where .isnull() and .notnull() methods are defined, these have additional methods named .isna() and .notna(), these are included for classes Categorical, Index, Series, and DataFrame. (GH15001).

The configuration option pd.options.mode.use_inf_as_null is deprecated, and pd.options.mode.use_inf_as_na is added as a replacement.