Questions tagged [list]
is for the list object in Lisp programming. A list represents a sequence of zero or more elements. Emacs Lisp relies extensively on the list data structure; it is a fundamental building block. Emacs provides many facilities for building, modifying, extending, and efficiently handling list data structures.
173
questions
4
votes
2
answers
352
views
Filter a list of strings to create a separate list of those that match a given prefix
If I have a list, (“apple” “pear” “grape” “apricot”) how do I create a new list with elements starting with the letter “a”? The new list will be: (“apple” “apricot”).
- 181
0
votes
2
answers
31
views
How to step into (apply ..) function when using Edebug?
When using edebug, stepping into a function call works.
But if I change the function call from
(foo args)
to
(apply '#foo args)
edebug says apply is built-in function and won't let me step into.
I ...
- 489
1
vote
3
answers
301
views
Does Emacs has a built-in function for unpacking lists with an arbitrary depth that keeps nil values?
What I'm looking for
I want to have a function that given the following inputs, returns the following outputs.
Input
(1 nil)
(1 (2) (nil))
(1 (2 (3)) (nil (nil)))
(1 (2 (3 (4))) (nil (nil (nil))))
(1 (...
- 398
-1
votes
1
answer
32
views
Print complete list [duplicate]
I am trying to print a list but I get a partial list when calling
(message "%S" mylist)
("richad" "richda" "ricahd" "ricadh" "ricdha" "...
- 1,183
0
votes
1
answer
55
views
How to unpack lists regardless of the depth? [duplicate]
I want to have a function that does the following
Input
'(1 (2) (3))
'(1 (2) ((3 4)))
'(1 (2) ((3 4) (5 6)))
'(1 (2) ((3 4) (5 6 (7 8))))
'(1 (2) ((3 4) (5 6 (7 8 (9 10)))))
Output
'(1 2 3)
'(1 2 3 4)...
- 398
2
votes
1
answer
50
views
add-to-list or push? Is there any disadvantage in using one over the other?
I've added a line in my early-init.el file that sets a background color to prevent the glare during startup.
;; Customize background color to prevent startup glare
(add-to-list 'default-frame-alist
...
- 391
0
votes
1
answer
49
views
Combining commands for two major modes
I want to extend the execution of the body of emacs-lisp-mode also to lisp-interaction-mode. How can I combine two conditions together?
(cond
((eq major-mode 'emacs-lisp-mode)
(let ( (...
- 1,183
-1
votes
1
answer
54
views
Print an alist in a named buffer
I want to print an alist in a specific named buffer, which I have to create if it does not exist. either by tabulated-list-format or using table-contents. How can I adapt these two functions to print ...
- 1,183
0
votes
1
answer
44
views
Elisp construct
What is this construct in elisp ?
'( ("approx" "approximately") ("appt" "appointment")
("apt" "apartment") ("dept" &...
- 1,183
0
votes
2
answers
21
views
kill-buffer ERROR: wrong-type-argument - can't programatically kill buffers
I'm trying to kill buffers after selecting them from buffer-list:
(kill-buffer
(cl-remove-if-not (lambda (b)
(and
(string-match-p "ein" (buffer-...
0
votes
2
answers
18
views
How do you filter buffer list in a script? [duplicate]
Let's say there are three buffers:
"buffer1.py"
"buffer2.rb"
"buffer3.ipynb"
How do you filter/glob that list to select a specific buffer aka
(switch-to-buffer "*....
2
votes
2
answers
161
views
Marking as safe all possible lists of strings
Following this answer, I put the following lines in a .dir-locals.el file:
((latex-mode
(TeX-engine . default)
(mode . latex )
(TeX-master . "main")
(ispell-buffer-session-localwords
...
- 163
1
vote
1
answer
24
views
Edit org-agenda Files
Is there a way to edit the files which are included in org-agenda?
I have a pretty long list and want to just tidy up a bit.
I know I have the variable stored in init.el, but it's just one long line ...
- 531
4
votes
1
answer
508
views
Is it faster to add an element at the beginning of a list with add-to-list than at the end?
I've noticed that some people use a t at the end of this code:
(add-to-list 'package-archives '("melpa" . "https://melpa.org/packages/") t)
that t makes it append at the end of ...
- 391
0
votes
1
answer
38
views
How can I return a list from this function given :str nil and 1 argument
I could not figure out how to get a list out of this (my/tf :str nil "foo" ).
This function returns a concatenated string of directories or a list.
Function Must:
Return a string when one ...
- 25
2
votes
2
answers
132
views
How do I get a return of multiple strings from a list?
I want this ("start" "--color=always" "--exclude=*pdf" "end") but I am getting this ("start" ("--color=always" "--exclude=*pdf") &...
- 151
7
votes
1
answer
132
views
“(equal a b)⇒t” whereas “(equal b a)⇒error”
GNU Emacs Lisp Reference Manual, 2.8 Equality Predicates:
Comparing circular lists may therefore cause deep recursion that leads to an error, and this may result in counterintuitive behavior such as (...
- 4,272
0
votes
0
answers
31
views
Why setf to add a new element failed in function body?
(setq orig '((a . 1)
(b . 2)))
(setq added '((b . 0)
(c . 3)
(d . 4)))
;; method 1
(mapc (lambda (x) (setf (alist-get (car x) orig) (cdr x))) added)
orig ;; =&...
- 1
1
vote
1
answer
65
views
Add a blank line between headings in the Global TODO list
My Global TODO list shows headings one after another, without any spacing between headings.
To me this looks a little crowded, and it would be easier to see the end of one heading and the start of the ...
- 148
-2
votes
2
answers
53
views
seq-mapn with array in lambda function
I am using the following function to make a list of lists.
(defun pmchart selectr nc)
"TODO."
(seq-mapn
(lambda (p q)
(message "p: %S" p)
(list q (append ...
- 1,183
-3
votes
1
answer
86
views
Adapting list according to array
I want to construct a list of lists using the function pmchart
(pmchart '("Peter" "John") [3 2] 5)
to produce
'(("Peter" "xxxxx" "xxxxx" "xxxxx&...
- 1,183
0
votes
1
answer
20
views
Updating values in a list
I have the following variable composed of two numbers.
(defvar recorder '(0 0))
Inside some function I want to update the first value in recorder. And in another function, I want to update the ...
- 1,183
0
votes
1
answer
162
views
Printing each element in list on separate line
I am using \n so that when printing the list, each element in the list gets a new line when calling message. I am trying to have a go at printing a list where each element does not have a \n at the ...
- 1,183
9
votes
6
answers
996
views
When is the first element in the argument list regarded as a function symbol and when not?
I'm learning elisp, and I just learned that the first element of a list is interpreted as a function symbol. I then learned how to define a function with defun. Here's the example from An Introduction ...
- 191
1
vote
2
answers
87
views
Why changing the value of this variable via add-to-list is not working?
Usually, I do the following to change a variable's value:
1 - I execute the command set-variable
2 - I pick cider-shadow-cljs-command
3 - I tweak the value changing it to be "shadow-cljs"
It ...
- 1,369
0
votes
1
answer
36
views
Working with a list of alists
I have a number of "alists".
(defconst assoc-table-1
'( ("frantic" . "fN") ("authentic" . "atN") ))
(defconst assoc-table-2
'( ("graphology&...
- 1,183
0
votes
1
answer
19
views
Reading the list produced by (mac-frame-geometry)
I just learned about the function (mac-frame-geometry). It produces a list in the form of:
'((outer-position 0 . 25)
(outer-size 1920 . 1055)
(external-border-size 0 . 0)
(title-bar-size 1920 . ...
- 1,202
0
votes
1
answer
37
views
Clear list when number of elements exceeds N
I have a list, and want to clear it with (setq slist '()). But I only want to do this when the number of elements exceeds the value N.
- 1,183
-3
votes
1
answer
58
views
Adding replacement strings to a list
I want to add replacements to matching words to a list called nscrip.
I already have a large number of lists that I use for dabbrev, written in the following form. Perhaps I can use these lists, or ...
- 1,183
1
vote
0
answers
31
views
Clearing a made list [closed]
I am adding to a list as I execute a number of functions. How can I clear the elements in the list by calling a function for such task.
- 1,183
0
votes
1
answer
23
views
Adding to a list when there is a match only
The following function replaces filenames and places the result in a list. Although the list gets filled, I do not want to add the filename when there is no match. How can I avoid sending non-...
- 1,183
1
vote
1
answer
184
views
How can I use `add-to-list` to add multiple elements to a list value of a variable?
Is this the way to use add-to-list with multiple entries?
(add-to-list 'auto-mode-alist
'(("\\.f\\'" . fortran-mode)
("\\.F\\'" . fortran-mode)
...
- 1,183
0
votes
3
answers
88
views
Using `let` with `list`
I have read that by default, a function returns the value of the last expression evaluated as the return value.
Does it mean that when using special form let, the value of the last expression in the ...
- 1,183
2
votes
1
answer
70
views
Why do stream-cons and cons behave differently?
I am trying to create a lazy sequence of the lines in the current buffer using the stream.el library. These two recursive functions both read the lines of the current buffer from point to the end of ...
- 131
1
vote
2
answers
100
views
How to randomize the order of elements in an alist?
I'm using ielm inside Emacs to randomize an associative list. I'm getting duplicate entries a lot of the time, not sure what I'm doing wrong?
(defun q ()
"Q."
(let ((alist))
(setf ...
- 167
0
votes
1
answer
36
views
Unclear wrong argument
The following expression:
(car input-method-function)
Give the following message:
Wrong type argument: listp, list
Why? input-method-function is list.
- 51
1
vote
2
answers
122
views
Incorporate a list of floats, into another list of floats, in numerical order, with remainders
In this example, there is a list of miscellaneous orphan floats '(9.9 10.1 10.3 10.5 10.7 10.9 11.1) that needs to be incorporated in numerical order into a second main / master list (10.0 10.2 10.4 ...
- 18.9k
1
vote
2
answers
54
views
Next greater or lesser number than ARG in a list of integers
In this example, there is a list of integers '(2527 1771 2107 2317). The variable arg is an integer, which may or may not be one of the integers in the list. Q: How can an Emacs user ...
- 18.9k
0
votes
0
answers
74
views
Why not build lists in-order? (instead of pushing to the front & reversing)
In emacs-lisp a common pattern is to build a list by adding to the font, then reversing it.
As it's possible to build the list by storing the last cons cell, then appending to it - it seems like a ...
- 8,406
2
votes
2
answers
43
views
ring: convert a ring back to a list -- keeping rotation
In the following example, the element (c fig) is the current-item. The user has chosen to rotate the ring forwards, by calling ring-next. How can a user return the revised list in its rotated state; ...
- 18.9k
1
vote
1
answer
61
views
Process of packages loading
It seems I totally do not understand the mechanism of package loading in Emacs.
I have in my init.el something like this:
(use-package elpy
:ensure t
:init
(elpy-enable)
:config
(defalias '...
- 143
0
votes
1
answer
46
views
(copy-sequence (cons 'foo 'bar)) => wrong-type-argument listp
In this example, there is a cons-cell (foo . bar) which needs a two (2) step approach so that it can be copied using copy-sequence:
First, there needs to be a test to identify this particular type of ...
- 18.9k
0
votes
1
answer
72
views
What does setcdr do to a list which is the return value of a function?
If I have something like this,
(setq first (list 'a 'b 'c))
(setq second (list 'x 'y 'z))
;; I know the let binding makes little sense but
;; I need it in the full version of the function.
(defun ...
- 1,555
0
votes
1
answer
81
views
How to extract tables names from an org file?
I have an org file with headlines and subheadlines containing tables. Each table has a name (i.e. each table starts with a #+name: tablename header). I'd like to generate a list containing all tables ...
- 1,185
1
vote
1
answer
218
views
How can I apply function `max` to a list of numbers?
I want to find the max element in a list of numbers.
(setq l (list 1 2 3 4 5))
What is an easy way to call the max function on l?
So far I have this but this seems convoluted:
(eval `(max ,@l))
It ...
- 177
0
votes
0
answers
26
views
Bullets in Lists (Org-Mode) [duplicate]
like asked here:
custom bullet style
Isn't there any way to use • in Org-mode lists? It would look much nicer than *...
I made a shortkey to insert • bullets, but they won't be recognized by Emacs as ...
- 31
0
votes
1
answer
26
views
Why does a stray period cause an error I associate with mismatched parens?
A typo that changed (foo) to (foo . ) in my .init file caused an Invalid read syntax: ) error.
I get why it's a syntax error. But why this error? I thought this error message reliably reflected ...
- 103
0
votes
1
answer
111
views
Any existing function to fix comma-separated list in parens-pair?
I am looking a way to programatically fix invalidly formatted code for programming languages that use relatively simple list expression of elements separated by commas (ie, not in C++).
For example I'...
- 754
2
votes
1
answer
42
views
How to merge overlapping ranges given a list of (min . max) cons cells?
Given a list of cons cells, what is an efficient way to merge overlapping ranges?
When any values minimum or maximum are within the bounds (inclusive) of any of the other cons cells in the list, these ...
- 8,406
0
votes
2
answers
56
views
How to remove an item from a list of unique items, returning true on success?
Sometimes a list is known to contain a list of unique items, where it is useful to check if the item exists in the list, removing it if it does.
This is an inefficient way to accomplish this:
(...
- 8,406