Re: Manipulating List Elements In Programs

*To*: mathgroup at smc.vnet.net*Subject*: [mg23968] Re: Manipulating List Elements In Programs*From*: "Atul Sharma" <atulksharma at yahoo.com>*Date*: Sun, 18 Jun 2000 03:00:50 -0400 (EDT)*Organization*: McGill University*References*: <8icdhn$9sk@smc.vnet.net>*Sender*: owner-wri-mathgroup at wolfram.com

When you use Delete this way, you haven't actually redefined your list z. As in this example, z hasn't been changed. In z= {a, b, c, d}; Delete[z, 3] z Out {a, b, d} {a, b, c, d} What you really want to do is redefine the list, as in In z=Delete[z,3] z Out {a, b, d} {a, b, d} In you case, you may also find z=Rest[z] a convenient way to trim element 1 from the list. Atul ------------------------------------------------------------------------- Atul Sharma MD, FRCP(C) Pediatric Nephrologist, McGill University/Montreal Children's Hospital Buz Barstow wrote in message <8icdhn$9sk at smc.vnet.net>... >Hi, > >I'm trying to write a program in Mathematica to automatically plot graphs >from text files that I've generated with a C program. It looks in the >working directory, and retrieves a list of all files with a .dat extension; > >files = FileNames["output*.dat"] > >Then, it gets the number of entries in that list; > >l = Length[files] > >And then uses this information to import each file individually and do a >ListPlot with each list; > >For[i = 1, i <= l, i++, > z = Import[ files[[i]]]; > title = z[[1]]; > lab = z[[2]]; > Delete[z, {1, 2}]; > ListPlot[z, AxesLabel -> lab, PlotLabel -> title] ] > >At the top of each output file there is a heading that I want to use as the >plot's title and two column headings that I want to use to label the axes. >Unfortunately, I can retrieve them and label the plot, but I can't delete >them, so when I include the title, I can't produce the plot. > >Does Mathematica prevent the programming calls deleting things, or am I >missing something? > >Thanks in advance, > >Buz > >