On 01/05/2017 11:41 AM, Alan Gauld via Tutor wrote:
On 05/01/17 13:29, S. P. Molnar wrote:
Fortran II using punched paper tape. Yes, am a rather elderly . . .).
You are not the only one, there are at least 2 more of us on
this list that started in that era...
short program to change frequency to wavelength for a plot of
ultraviolet spectra. I have attached a pdf of the program.
This is a text list so attachments usually get stripped off.
Please post the code in the body of the email using plain text
formatting.
To change the frequency to wave length I did the following:
p=1/1e7
p = 1e-7
wave_length = p*np.array(frequency)
I don't really use numpy so don't know what that line does.
But assuming it applies the multiplication to each array element
I'd probably use:
wave_lengths = [p*f for f in frequencies]
or possibly
wave_lengths = map(lambda f: p*f, frequencies)
where frequencies was a tuple/list of frequency values.
However...
(The relationship between wavelength and frequency is: wavelength =
1.0e7/frequency, where 1e7 is the speed of light)
That formula doesn't look like the one you use above
if my guess is correct. That would look like:
wave_length = [1e7/f for f in frequencies]
ie positive exponent and division instead of multiplication
Apparently what I have managed to do is divide each element of the frequency
list by 1/1e7.
What I want to do is divide 1e7 by each element of the freqquency list.
How di I do this?
Rearrange the equation and use division instead of multiplication
I think that by calculating 1/p you have made things much more
complicated - unless there is some subtle arithmetic magic going
on that I'm missing?
Many thanks for the reply and your suggestions.
As it happens, I stumbled on the solution through trial and error.
The correct line is: wave_length = 1e7/np.array(frequency).
All is now well.
--
Stephen P. Molnar, Ph.D. Life is a fuzzy set
www.Molecular-Modeling.net Stochastic and multivariate
(614)312-7528 (c)
Skype: smolnar1
_______________________________________________
Tutor maillist - Tutor@python.org
To unsubscribe or change subscription options:
https://mail.python.org/mailman/listinfo/tutor
