Re: Problem with Position
- To: mathgroup at smc.vnet.net
- Subject: [mg119648] Re: Problem with Position
- From: Dominic Wörner <dominic.woerner at mpi-hd.mpg.de>
- Date: Thu, 16 Jun 2011 03:59:59 -0400 (EDT)
- References: <201106151120.HAA22862@smc.vnet.net> <BANLkTindQ9jZN_wLzsAy9pTM+Udt3T+K2g@mail.gmail.com>
Hi Leonid, Many thanks for your advise but I still have one problem When I write to a file using WriteString[str, ToString[number]] it will be written in OutputForm. Now I thought using your advice It should work with Position[..., x_/;x==OutputForm[number]] but unfortunately it doesn't Am 15.06.2011 um 12:59 schrieb Leonid Shifrin: > Hi Dominic, > > This is most likely a symbolic/numerical issue. Position is based on symbolic rather than numeric comparisons. > You may have success with > > Flatten@Position[data[[All,1]],x_/;x==0.785398] > > Here is one of the most recent related discussions: > > http://stackoverflow.com/questions/5750623/using-position-correctly > > Regards, > Leonid > > > On Wed, Jun 15, 2011 at 3:20 PM, Dominic W=F6rner <dominic.woerner at mpi-hd.mpg.de> wrote: > Hi, > > I have to import data from a csv file. And I get a structure data[[rows]]={first, second,...}. > Now I want to find the rows in which, say the first entry has a specific values. > By just looking at the data there are for example entries with value 0.785398. > But when I try Flatten@Position[data[[All,1]],0.785398] or with ToString[0.785398] I just get {} > > What's the problem here? > > Best, > Dominic > >
- References:
- Problem with Position
- From: Dominic Wörner <dominic.woerner@mpi-hd.mpg.de>
- Problem with Position