Discussion:
[pytables-users] How do you query a 'frame_table' object?
Shan
2016-07-19 16:07:22 UTC
Permalink
I apologise as this is a beginner's question:

I have the following pandas dataframe:


import pandas as pd
df = pd.read_table(fname.dat)

So, I create/ open an existing HDFStore file:

store = pd.HDFStore('store.h5')

To index a subset of columns, I simply use

store.append('key_name', df, data_columns=['colA','colB','colZ'])


Apparently, `HDFStore.append() `saves pandas dataframes per default in
`table` format. However, it looks like it is actually a 'frame_table'
object:

store

outputs

/key_name frame_table
(typ->appendable,nrows->3254334,ncols->14,indexers->[index],dc->[colA,
colB, colZ]) How do I efficiently index this object? Normally, the query
would be result = [row for row in table.where('colA==22 & colB==45')] But
would does one do this for a `frame_table` object?
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