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Topic: How to remove the "0." from "0. + 1.41774i"
Replies: 8   Last Post: Jun 23, 2013 10:50 PM

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 Murray Eisenberg Posts: 2,105 Registered: 12/6/04
Re: How to remove the "0." from "0. + 1.41774i" [Revised]
Posted: Jun 22, 2013 3:27 AM

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@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

Date Subject Author
6/20/13 Mike Bayville
6/21/13 Nasser Abbasi
6/21/13 Mike Bayville
6/21/13 cj.girlie@gmail.com
6/21/13 Bill Rowe
6/22/13 Murray Eisenberg
6/23/13 Simons, F.H.