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Conditional Import
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sebastian...@googlemail.com
Oct 26, 2011, 5:46:46 PM10/26/11
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Hi!
I would like to import data from a very large text file. If I import all the data, Mathematica takes around 9 h to complete. Therefore I would like to import conditionally, that is for example only every 5th element. It would probably be best to do this using low level function. I have found a help topic on this (developing an import converter), however I can not get it to work. Specifically, I do not understand how to implement my own import converter, and how I can then use this to only import every 5th element of a file.
Thank you!
I would like to import data from a very large text file. If I import all the data, Mathematica takes around 9 h to complete. Therefore I would like to import conditionally, that is for example only every 5th element. It would probably be best to do this using low level function. I have found a help topic on this (developing an import converter), however I can not get it to work. Specifically, I do not understand how to implement my own import converter, and how I can then use this to only import every 5th element of a file.
Thank you!
Leonid Shifrin
Oct 27, 2011, 6:38:32 AM10/27/11
to
As an alternative to writing your own import converter, which is a heavier
approach, you may try Read/ReadList or even BinaryRead/BinaryReadList. These
are fast (especially Binary..) lower-level functions which read from a
stream and might be enough for your purposes.
Regards,
Leonid
approach, you may try Read/ReadList or even BinaryRead/BinaryReadList. These
are fast (especially Binary..) lower-level functions which read from a
stream and might be enough for your purposes.
Regards,
Leonid
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