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Re: How to remove the "0." from "0. + 1.41774i" [Revised]

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• Subject: [mg131259] Re: How to remove the "0." from "0. + 1.41774i" [Revised]
• From: Murray Eisenberg <murray at math.umass.edu>
• Date: Sat, 22 Jun 2013 03:32:08 -0400 (EDT)
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Unless you'd be satisfied to have just a display form with no "0." included, e.g., as a string, I don't see how you can do what you ask. You might be tempted to try something like:

  imchop[z_] :=
      Which[z \[Element] Reals, z,
            Head[z] == Complex && Re[z] != 0, z,
            Head[z] == Complex && Re[z] == 0, Im[z] I]

But it won't handle the case at issue, e.g.:

   imchop[0. + 1.41774 I]
0. + 1.41774 I

And the reason is that after extracting the imaginary part 1.41774 and multiplying by I, you have a number whose FullForm is

   Complex[0.`, 1.417741]

and hence will display as the very same 0. + 1.41774 I.


> I have some to realize that I failed to describe the context of my request.
>
> I am hope to identify or create a function, e.g., mikechop[t_], such that the argument could be a real or complex number, and if it is a complex number such as:
>
> 0. + 1.41774i
>
> or
>
> 1.2313 x 10^(-16) + 1.41774i
>
> the output will be:
>
> 1.41774i
>
> otherwise it will be the real or complex number that was input.
>
> This is for inclusion in code that I write.
>
> Sorry for not properly describing the end use.
>
> Humbly,
>
> Mike
>
>
>
>
>
> On Thursday, June 20, 2013 4:01:33 AM UTC-4, Mike Bayville wrote:
>> Can anyone suggest a built-in function for removing  the "0." from "0. + 1.41774i"?
>>
>>
>>
>> Thanks!
>>
>>
>>
>> Mike
>>
>>
>>
>> INPUT
>>
>> A={{-1.2, 1.5}, {-2.3, 1.2}};
>>
>> Clear[eigenvalue];
>>
>> {eigenvalue[1], eigenvalue[2]} = Chop[Eigenvalues[A]]
>>
>> Chop[eigenvalue[1]]
>>
>> Chop[eigenvalue[2]]
>>
>>
>>
>> OUTPUT
>>
>> {0. + 1.41774i, 0. - 1.41774i}
>>
>> 0. + 1.41774i
>>
>> 0. - 1.41774i

---
Murray Eisenberg                                    murray at math.umass.edu
Mathematics & Statistics Dept.      
Lederle Graduate Research Tower            phone 413 549-1020 (H)
University of Massachusetts                               413 545-2838 (W)
710 North Pleasant Street                         fax   413 545-1801
Amherst, MA 01003-9305

• Follow-Ups:
  • Re: How to remove the "0." from "0. + 1.41774i" [Revised]
    • From: Fred Simons <f.h.simons@tue.nl>

• References:
  • How to remove the "0." from "0. + 1.41774i" [Revised]
    • From: Mike Bayville <mike.bayville@gmail.com>