我在一列中有“NA”（意思是北美），在Pandas读取CSV后显示为空白

Question

我有一个CSV文件，其中的Country列包含国家代码。在这里，“NA”的意思是北美。我需要把它转换成UTF-8格式。使用下面的代码时，带有“NA”的行在导出的文件中显示为空白：

df = pd.read_csv(filepath, encoding='UTF-8')
df.to_csv(r'path+filename',header=None ,encoding = 'UTF-8', index = False)

比如说,

输入文件：

Week Country PL Sales$
W01   AE     0I  250
W02   NA     0I  130

输出文件：

Week Country PL Sales$
W01   AE     0I  250
W02          0I  130

我尝试用“NA”填充源文件中的其他列，这些列现在也是空白的

Answer 1

'NA'是na_values中的默认NaN值之一。在使用^{}读取csv文件时，需要指示pandas排除默认值：

keep_default_na: bool, default True

Whether or not to include the default NaN values when parsing the data. Depending on whether na_values is passed in, the behavior is as follows:

If keep_default_na is True, and na_values are specified, na_values is appended to the default NaN values used for parsing.

If keep_default_na is True, and na_values are not specified, only the default NaN values are used for parsing.

If keep_default_na is False, and na_values are specified, only the NaN values specified na_values are used for parsing.

If keep_default_na is False, and na_values are not specified, no strings will be parsed as NaN.

Note that if na_filter is passed in as False, the keep_default_na and na_values parameters will be ignored.

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这应该可以做到：

df = pd.read_csv(filepath, encoding='UTF-8', keep_default_na=False)

根据您想要执行的其他操作，您可能还需要相应地定义na_values