Input, output troubles me ...

*To*: mathgroup at smc.vnet.net*Subject*: [mg70010] Input, output troubles me ...*From*: "luigirmailbox-mathematica at yahoo.it" <luigirmailbox-mathematica at yahoo.it>*Date*: Sat, 30 Sep 2006 05:12:38 -0400 (EDT)*Reply-to*: luigirmailbox-mathematica at yahoo.it

Dear Friends I have been using Mathematica for text file processing for a long time. I found it's a valuable tool for text complex manipulations. The strategy I was used to apply is well condensed in this childish example: --------------------------------- (*loading the content*) dummy = Import["c:\\myDir\\inputFile.txt", "Lines"]; (*processing it*) dummy = Select[dummy, (# != "a") &]; (*exporting it*) Export["c:\\myDir\\outpuFile.txt", dummy, "Lines"]; --------------------------------- Now I have to face huge file (up to 5,6 Gb sized) and the previous technique mostly crashes my systems. I would like to process a single line, rather than the whole load, doing something similar what a classical programmig language does: --------------------------------- Open "c:\\myDir\\inputFile.txt" for Input As #1 Open "c:\\myDir\\outputFile.txt" for Input As #2 Do While Not Eof(#1) Line Input #1, dummy$ If dummy$ <> "a" Then Print #1, dummy$ Loop Close #1 Close #2 --------------------------------- I tried this (and many others!) trick: --------------------------------- stream1 = OpenRead["c:\\myDir\\inputFile.txt"]; stream2 = OpenWrite["c:\\myDir\\outputFile.txt"]; While[ dummy != EndOfFile, dummy = Read[stream1, "String"]; If[dummy != "a", Write[stream2, dummy]]; ] Close[stream1]; Close[stream2]; --------------------------------- But it doesn't work: when inputFile is a b c d outputFile is void, not b c d as expected. Plaese can someone help me? Thanks for your attention. Goobye.