RE: Editing .txt file in Octave

[Mike Miller]

On Thu, 18 Mar 2010, socware wrote:

> Hello
> I am in Windows XP (Home) and using Octave 3.2.4 over cygwin.
>
> My file looks like this
>
> 30m              399.14n
> 31m              412.216n
> 32m              425.291n
> 33m              438.367n
> 34m              451.442n
>
>
> There are two columns. I want to use the values from both the columns as
> range of x and y respectively in a for loop.
>
> My problem is first I need to change the format from 30m to .00030 or to
> some other format like 30e-3

The two answers you suggest are different:  .00030 != 30e-3
Maybe m means micro and you meant .000030 or 30e-6.
Or maybe m means milli and you meant .030 or 30e-3.

> Secondly each column have more than 1000 values and I want to use all of 
> them and also if possible specify to use for instance the first 500 
> values or values in between too.
>
> Thank you for the feedback and help.

You are using Cygwin, so if you don't have perl, install it.  Then do 
this:

perl -pe 's/m/e-3/g ; s/n/e-9/g' infile > outfile

Where your original file is "infile" and you create "outfile".

I am assuming m is micro or 10^-3 and n is nano or 10^-9.  If you also 
have u for micro (10^-6), then you can do this to get all three:

perl -pe 's/m/e-3/g ; s/u/e-6/g ; s/n/e-9/g' infile > outfile

This replaces all m, u and n characters, so it implicitly assumes that 
they play only this role (setting the exponent) in the file.

Mike