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Re: Creating a list
From: |
Cecil Westerhof |
Subject: |
Re: Creating a list |
Date: |
Thu, 19 Nov 2009 11:59:19 +0100 |
User-agent: |
Gnus/5.11 (Gnus v5.11) Emacs/22.3 (gnu/linux) |
David Kastrup <dak@gnu.org> writes:
>> At the moment I create a list with:
>> (setq ret-val (cons total-amount (cons current-amount ())))
>> I thought about doing it with:
>> (setq ret-val (cons total-amount '(current-amount)))
>>
>> But then the second value is the string current-amount
>
> Wrong. The _symbol_ current-amount.
When evaluating I got:
(1570378.2570192777 current-amount)
That is why I thought I got the string.
> I would really recommend taking a look at the Introduction to Elisp
> Programming
>
> (info "(eintr)")
> Press C-x C-e here --^
I'll do that.
> This is sort of obvious:
>
> (setq ret-val (list total-amount current-amount))
Works like a charm.
For the curious. This is the function I wrote:
(defun arithmetic-row(start-amount interest years)
(let ((current-amount start-amount)
(index 1)
(multiplication-factor (+ 1 (/ interest 100.0)))
(ret-val)
(total-amount start-amount))
(if (< years 1)
(setq ret-val nil)
(while (< index years)
(setq index (1+ index))
(setq current-amount (* current-amount multiplication-factor))
(setq total-amount (+ total-amount current-amount)))
(setq ret-val (list total-amount current-amount)))))
And it can be called with:
(arithmetic-row 28000 4 30)
With the call it is calculated how much someone earns in total in 30
years when he starts with 28000 a year and get every year a raise of
4%. This total is the first value of the list, the amount earned in the
last year is the second value of the list.
This is a arithmetic solution. But for example in year 3 now is earned
31496.192000. In real life this would be 31496.19. So before using the
value it should be rounded, but until now I did not a round
function. But maybe I'll find that in the intro.
--
Cecil Westerhof
Senior Software Engineer
LinkedIn: http://www.linkedin.com/in/cecilwesterhof
- Creating a list, Cecil Westerhof, 2009/11/19
- Re: Creating a list, David Kastrup, 2009/11/19
- Re: Creating a list,
Cecil Westerhof <=
- Re: Creating a list, David Kastrup, 2009/11/19
- Re: Creating a list, Cecil Westerhof, 2009/11/19
- Re: Creating a list, Barry Margolin, 2009/11/19
- Re: Creating a list, Cecil Westerhof, 2009/11/19
- Re: Creating a list, Pascal J. Bourguignon, 2009/11/19
- Re: Creating a list, David Kastrup, 2009/11/19
- Re: Creating a list, Cecil Westerhof, 2009/11/19
- Re: Creating a list, Pascal J. Bourguignon, 2009/11/19
Gnus: Some new mails are automatically marked as 'O', Wang Lei, 2009/11/19