pandas AttributeError: 'Series' 对象没有属性 'notna'
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AttributeError: 'Series' object has no attribute 'notna'
提问by Aman Singh
i have a csv file with multiple columns containing empty strings. Upon reading the csv into pandas dataframe, the empty strings get converted to NaN.
我有一个多列包含空字符串的 csv 文件。将 csv 读入 Pandas 数据帧后，空字符串将转换为NaN。
Now i want to append a string tag-to the strings already present in the columns but to only those that have some values in it and not on those with NaN
现在我想将一个字符串附加tag-到列中已经存在的字符串，但只附加到那些有一些值的字符串而不是那些带有NaN的字符串
this is what i was trying to do:
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)
and this is the error I'm getting:
这是我得到的错误：
AttributeError: 'Series' object has no attribute 'notna'
the final output that i want should be something like this:
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
回答by jezrael
I believe you need maskfor add tag-to all columns together:
我相信您需要mask一起添加tag-到所有列：
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))
You need upgrade to last version of pandas, 0.21.0.
您需要升级到最新版本的Pandas，0.21.0.
You can check docs:
您可以查看文档：
In order to promote more consistency among the pandas API, we have added additional top-level functions
isna()andnotna()that are aliases forisnull()andnotnull(). 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.
为了促进大PandasAPI之间的一致性，我们增加了额外的顶级功能
isna()和notna()是为别名isnull()和notnull()。命名方案现在类似的方法更加一致.dropna()和.fillna()。此外，在定义 .isnull() 和 .notnull() 方法的所有情况下，这些方法都有名为.isna()and 的附加方法.notna()，这些方法包含在 Categorical、Index、Series 和 DataFrame 类中。(GH15001)。不推荐使用配置选项 pd.options.mode.use_inf_as_null，并添加 pd.options.mode.use_inf_as_na 作为替代。
