Re: How can I do a "grep -v" equivalent in Import[]?

*To*: mathgroup at smc.vnet.net*Subject*: [mg91849] Re: How can I do a "grep -v" equivalent in Import[]?*From*: David Bailey <dave at Remove_Thisdbailey.co.uk>*Date*: Wed, 10 Sep 2008 05:08:30 -0400 (EDT)*References*: <g9t6mq$j8s$1@smc.vnet.net> <200809081010.GAA27650@smc.vnet.net> <ga5kov$r8g$1@smc.vnet.net>

Jason Ledbetter wrote: > Valid point: > This will likely line wrap: > > --snip-- > CPU NFS CIFS HTTP Total Net kB/s Disk kB/s Tape kB/s Cache > Cache CP CP Disk FCP iSCSI FCP kB/s > in out read write read write age > hit time ty util in out > 24% 0 741 0 767 9381 6144 88815 0 0 81011 9 > 98% 0% - 31% 0 26 0 0 > --snip-- > > I'm trying to avoid importing through a pipe and I'm trying to avoid > preprocessing the data (for no real reason other than trying to get a handle > on data processing in Mathematica). > > I've done the following: > > importTemp = Import[ToFileName[Directory[], "input.txt"], {"Lines"}]; > regexMatch = "^\d{2}.*"; > sysstat = StringCases[importTemp, RegularExpression[regexMatch]]; > > which gets me ALMOST what I'm looking for.... I end up with the the > non-matched lines being empty data sets which Part:partw doesn't like. > > e.g. output is like this: > > {{}, {}, {"24"}, {"29"}, ... > > > Thank you very much for the replies to date. > > -jbl > I am still not 100% sure I know what you want to do, but assuming you want just the first two digits of lines that start with 2 digits, I am still not 100% sure I know what you want to do, but assuming you want just the first two digits of lines that start with 2 digits, tmp2 = Select[importTemp, StringMatchQ[#, DigitCharacter ~~ DigitCharacter ~~ __] &]; Map[StringTake[#, 2] &, tmp2] Alternatively, you could clean up the output that you have obtained already: {{}, {}, {"24"}, {"29"}} /. {} :> Sequence @@ {} With all the new string matching functionality, it is rarely necessary to resort to C preprocessing, unless speed is critical (i.e. your input file is very big!). David Bailey http://www.dbaileyconsultancy.co.uk

**References**:**Re: How can I do a "grep -v" equivalent in Import[]?***From:*David Bailey <dave@Remove_Thisdbailey.co.uk>