[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: How to read an integer from the minibuffer
From: |
Emanuel Berg |
Subject: |
Re: How to read an integer from the minibuffer |
Date: |
Fri, 12 Nov 2021 20:25:30 +0100 |
User-agent: |
Gnus/5.13 (Gnus v5.13) Emacs/29.0.50 (gnu/linux) |
Jean Louis wrote:
>> We see a problem BTW that `string-to-number' returns 0
>> on error!
>
> That problem I have solved in rcd-utilities.el with:
>
> (defun string-is-number-p (s)
> "Return number only if string is pure number,
> otherwise NIL."
A number is said to be pure if
1. It has even number of digits.
2. All the digits are either 4 or 5.
3. And the number is a palindrome.
First few pure numbers are 44, 55, 4444, 4554, 5445, 5555 ... [1]
Also the familiar docstring functional parameter issue.
> (let ((s (string-trim s)))
> (cond ((seq-empty-p s) nil)
> ((string-match "[^0123456789\\.]" s) nil)
Use a char class or an interval?
> ((numberp (string-to-number s)) (string-to-number s)))))
(string-is-number-p "-0")
(string-is-number-p "-5.3")
[1] https://www.geeksforgeeks.org/find-the-first-n-pure-numbers/
--
underground experts united
https://dataswamp.org/~incal
- Re: How to read an integer from the minibuffer, (continued)
- Re: How to read an integer from the minibuffer, Gregory Heytings, 2021/11/11
- Re: How to read an integer from the minibuffer, Emanuel Berg, 2021/11/11
- Re: How to read an integer from the minibuffer, Gregory Heytings, 2021/11/11
- Re: How to read an integer from the minibuffer, Emanuel Berg, 2021/11/11
- Re: How to read an integer from the minibuffer, Gregory Heytings, 2021/11/11
- Re: How to read an integer from the minibuffer, Emanuel Berg, 2021/11/11
- Re: How to read an integer from the minibuffer, Gregory Heytings, 2021/11/11
- Re: How to read an integer from the minibuffer, Emanuel Berg, 2021/11/11
- Re: How to read an integer from the minibuffer, Jean Louis, 2021/11/12
- Re: How to read an integer from the minibuffer,
Emanuel Berg <=
- Re: How to read an integer from the minibuffer, Jean Louis, 2021/11/12
- Re: How to read an integer from the minibuffer, Emanuel Berg, 2021/11/12
- Re: How to read an integer from the minibuffer, Jean Louis, 2021/11/13
- Re: How to read an integer from the minibuffer, Emanuel Berg, 2021/11/16
- Re: How to read an integer from the minibuffer, Jean Louis, 2021/11/12
- Re: How to read an integer from the minibuffer, Jean Louis, 2021/11/12
- Re: How to read an integer from the minibuffer, tomas, 2021/11/12
- Re: How to read an integer from the minibuffer, Emanuel Berg, 2021/11/12
- Re: How to read an integer from the minibuffer, tomas, 2021/11/12
- Re: How to read an integer from the minibuffer, Emanuel Berg, 2021/11/12