确定 pandas HDF文件中DataFrame的格式 [英] Determine format of a DataFrame in pandas HDF file

问题描述

有一个HDF文件'file.h5'，保存到其中的pandas DataFrame(或系列)的键名是'df'.如何确定"df"以哪种格式(即固定"或表格")保存到文件中?

There is an HDF file 'file.h5' and the key name of a pandas DataFrame (or a Series) saved into it is 'df'. How can one determine in what format (i.e. ‘fixed’ or ‘table’) was 'df' saved into the file?

谢谢您的帮助！

推荐答案

有点晚了，但也许有人会觉得有用.

A bit late but maybe someone else may find it helpful.

您可以解析 HDFStore.info() . table格式的对象的类型为appendable:

You can parse the output of HDFStore.info(). Objects in table format have the type appendable:

>>> print(h5_table.info())
<class 'pandas.io.pytables.HDFStore'>
File path: /tmp/df_table.h5
/df            frame_table  (typ->appendable,nrows->2,ncols->2,indexers->[index],dc->[])

>>> print(h5_fixed.info())
<class 'pandas.io.pytables.HDFStore'>
File path: /tmp/df_fixed.h5
/df            frame        (shape->[2,2]) 

这是一个最小的示例(即对丢失的文件或密钥没有错误处理)示例:

This is a minimal (i.e. without error handling for missing file or key) example:

def get_hd5_format(path, key):
    with pd.HDFStore(path) as store:
        info = store.info()
    return 'table' if 'typ->appendable' in next(k for k in info.splitlines()[2:] if k.startswith('/'+key)).split()[2] else 'fixed'

示例用法:

>>> get_hd5_format('/tmp/df_table.h5', 'df')
'table'
>>> get_hd5_format('/tmp/df_fixed.h5', 'df')
'fixed'

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