TypeError: read_hdf() takes exactly 2 arguments (1 given)

hdf5, pandas, pytables, python

Solution

Having never worked with hdf files before I was able to use the online docs to cook an example:

In [59]:
# create a temp df and store it
df_tl = pd.DataFrame(dict(A=list(range(5)), B=list(range(5))))
df_tl.to_hdf('store_tl.h5','table',append=True)
In [60]:
# we can simply read it again and the keys are displayed
store = pd.HDFStore('store_tl.h5')
# keys will be displayed in the output
store
Out[60]:
<class 'pandas.io.pytables.HDFStore'>
File path: store_tl.h5
/table            frame_table  (typ->appendable,nrows->5,ncols->2,indexers->[index])
In [61]:
# read it back in again
t = pd.read_hdf('store_tl.h5', 'table')
t
Out[61]:
   A  B
0  0  0
1  1  1
2  2  2
3  3  3
4  4  4

So basically just loading it using `HDFStore` and passing the path and then just displaying the object will print the keys in the output.

Problem

How to open a HDF5 file with `pandas.read_hdf` when the keys are not known? ``` from pandas.io.pytables import read_hdf read_hdf(path_or_buf, key) pandas.__version__ == '0.14.1' ``` Here the key parameter is not known. Thanks

Original source