Forwarding, ~Josh On Apr 30, 2012, at 5:04 PM, pytables-users-boun...@lists.sourceforge.net wrote: > From: Christian Werner <freizeitbeauftrag...@googlemail.com> > Date: April 30, 2012 5:03:59 PM GMT+02:00 > To: pytables-users@lists.sourceforge.net > Subject: How would I update specific rows from a table with rows of a second > table? > > > Hi group. > > Please consider this scenario. I have produced a large h5 file holding the > outcome of some simulations (hdf file holds some groups and about 5 tables, > but for my question this does not matter). > How I had to rerun my simulation but only for certain fields and thus I have > a second h5 file with the same structure but only for certain fields of the > original file (old age classes, see below). > > Or to be more verbose: > > Table (original) > id year species age data1 data2 data3 ... > 1 1990 spruce 75 1.2 3.2 3.3 ... > 1 1991 spruce 75 1.3 3.1 2.2 ... > ... > 1 1990 spruce 125 1.1 2.1 1.5 ... > ... > 1 1990 pine 145 1.1 2.1 1.5 ... > ... > 2 1990 spruce 45 1.2 3.2 3.3 ... > 2 1991 spruce 55 1.3 3.1 2.2 ... > ... > > I had to rerun my simulations for old vegetation classes. So this table only > contains the following lines (e.g., spruce age > 80) > > Table (new) > id year species age data1 data2 data3 ... > ... > 1 1990 spruce 125 1.1 2.1 1.5 ... > ... > 1 1990 pine 145 1.1 2.1 1.5 ... > > So basically I need to use the rows of the new table and overwrite the > corresponding rows of the old table to form the updated one. I do need to > retain the original order (sort order id > year > species > age). Those > columns combined give a unique row identifier... > > The final table would have the same size and order as the original table with > only the rows containing data for old age classes updated with the new > simulation results... > > Can anyone give me a hint how to achieve this? > > I guess I need to introduce a new (unique index) column first in both tables > (e.g., combining id + year + species + age so I can match those rows by this > identifier), right? Does anyone have some example code for me? > > Problem is, the 2 h5 files are about 7GB each. > > Cheers, > Christian > > >
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