Re: Read last expression in a file?

*To*: mathgroup at smc.vnet.net*Subject*: [mg116163] Re: Read last expression in a file?*From*: Mark McClure <mcmcclur at unca.edu>*Date*: Thu, 3 Feb 2011 05:34:48 -0500 (EST)

On Sat, Jan 29, 2011 at 7:43 PM, Ramiro <ramiro.barrantes at gmail.com> wrote: > I wrote a program that generates a lot of Mathematica output. > Now I need to restart it using the very last expression of such output > as the new input. However, I can't find a way to only read the last > expression in a file, something like a Read that would start at the > end. This can be done using Mathematica's low level file manipulation commands, such as Read and SetStringPosition. Here's an example. First, we create a file to play with. data == RandomInteger[{0, 1}, {100000, 100}]; Export["temp.txt", data]; If you examine the contents of temp.txt, you will find that it is a 30MB file containing one valid Mathematica list per line. The following method depends on the file containing one valid expression per line. strm == OpenRead["temp.txt"]; p == SetStreamPosition[strm, Infinity]; While[ Read[strm, Character] ==!== "\n", p == SetStreamPosition[strm, p - 1]]; lastLine == Read[strm] Close[strm] Mark McClure