#Hierarchical Data Format, commonly abbreviated HDF, HDF4, or HDF5 is a library and multi-object file format for the transfer of graphical and numerical data between computers. It was created by the NCSA, but is currently maintained by The HDF Group. The freely available HDF distribution consists of the library, command-line utilities, test suite source, Java interface,etc.

#HDF supports several different data models, including multidimensional arrays, raster images, and tables. Each defines a specific aggregate data type and provides an API for reading, writing, and organizing the data and metadata. New data models can be added by the HDF developers or users.

#PyTables is built on top of the HDF5 library, using the Python language and the NumPy package (it also supports numarray and Numeric right out-of-the-box). It features an object-oriented interface that, combined with C extensions for the performance-critical parts of the code (generated using Pyrex), makes it a fast, yet extremely easy to use tool for interactively dealing with, processing and searching very large amounts of data. One important feature of PyTables is that it optimizes memory and disk resources so that data takes much less space (specially if on-flight compression is used) than other solutions such as relational or object oriented databases.

#Pytables code follows:
