6 ms·

Sorting in Emacs

152 points by susam 3y ago

shepmaster 3y ago
I often want to sort within a line: [“zoo”, “cow”] Would become [“cow”, “zoo”] Any tips on how to do that? Ideally using just built in functions… I usually insert newlines between the elements, use a line-based sort, then recombine the lines. That works but is more tedious than I’d like. I’ve never taken the time to wrap that logic it in a function because it’s infrequent and it seems like it’s always slightly different.
- G3rn0ti 3y ago
  Keyboard macro. You convert the arrays into lines, you sort the result and then turn them back into arrays. If you do this often you could store the macro as an interactive command.
  - agumonkey 3y ago
    and for larger lists maybe a C-u shell-command-on-region to a script
- deleted 3y ago
  [deleted]
- pasc1878 3y ago
  Why bother recombining the lines?
  - CanaryLayout 3y ago
    Mostly to pretty it back up into the original shape (so it matches what was already in git)
    - pasc1878 3y ago
      Take one hit on format - your change is also only a format change.
- kroger 3y ago
  I found this on the Emacs Wiki [1]. It seems to work: (defun sort-symbols (reverse beg end) "Sort symbols in region alphabetically, in REVERSE if negative. See `sort-words'." (interactive "*P\nr") (sort-regexp-fields reverse "\\(\\sw\\|\\s_\\)+" "\\&" beg end)) [1]: https://www.emacswiki.org/emacs/SortWords https://www.emacswiki.org/emacs/SortWords
- tom_ 3y ago
  Copy to clipboard, paste into your interactive Python window, and use as the argument to sorted. Copy and paste the interpreter's output back into your code.
  - owl57 3y ago
    You technically described how to make a word sorting macro execute arbitrary code. Fascinating to think how that doesn't mean it's bad advice. That is, unless your threat model includes targeted attacks by three-letter-scale adversaries — and then you maybe just don't open untrusted files in Emacs or use advice from strangers on HN.
    - tom_ 3y ago
      That's a good point. My assumption, not that I ever stated it, was that the list would be one you'd typed out yourself, or was one that was just there in code already, and you could verify by eye that it's just string literals. Using Python's eval with empty globals and locals dicts (consult the docs) could make this safer, though I've only ever had to use that for defending against accidents rather than malice. And now this quick thing is becoming increasingly complicated, and maybe you'd be better off engineering it properly.
    - ktm5j 3y ago
      This is actually a rather common thing to do.. I have functions that run shell commands in my spacemacs config to do things like this. For example I've got one that runs `date` to insert today's date in a particular format.
  - deleted 3y ago
    [deleted]
  - lvass 3y ago
    >Copy to clipboard, paste into your interactive Python window python-shell-send-statement, it's built into Emacs's python mode.
    - 3y ago
- brunoqc 3y ago
  http://yummymelon.com/devnull/moving-text-elegantly-in-emacs.html http://yummymelon.com/devnull/moving-text-elegantly-in-emacs... maybe
- natrys 3y ago
  Probably simplest is to not overthink and just write elisp, which is a fairly normal language. (defun my-sort-list () (interactive) (when (not (looking-at (rx "["))) (search-backward "[" nil t)) (when-let* ((line (thing-at-point 'sexp t)) (items (split-string (substring line 1 -1) (rx ",") t (rx blank))) (sorted (string-join (sort items #'string-lessp) ", "))) (kill-sexp) (insert "[" sorted "]"))) I don't think I am using any non-builtin function here, though I think a few exceptions like s.el, f.el and dash.el can make things much easier.
  - minhm 3y ago
    "split-string" works well for this situation but for a case where there are commas inside some of the strings it would chop in the middle of those strings. So for the latter case and assuming the commas are consistently formatted, a safer approach might be starting in front of the first s-expression and then traversing to the tail of each s-expression with "forward-sexp" and check to see if a comma is there as expected and then delete the comma there (except for the last item with no comma) .
    - natrys 3y ago
      Yeah that's the classic comma in CSV problem. The solution is to indeed use a proper grammar/parser. The "forward-sexp" understands that as per major-mode rule as you say. Another more modern and declarative solution would be to take advantage of the full parse tree at your disposal thanks to tree-sitter (available in Emacs 29.1). Then you can simply do: (let ((list (treesit-thing-at-point "list" 'nested)) (query "(list (string (string_content) @item))")) (cl-loop for (_ . item) in (treesit-query-capture list query) collect (treesit-node-text item t)))
- deleted 3y ago
  [deleted]
- gnuvince 3y ago
  Select the line, then type C-u M-| jq -c sort
  - gumby 3y ago
    I've been using Emacs for over 40 years but still find the shell my go-to sorting approach. Right tool for the job and all that.
    - JNRowe 3y ago
      I lean a fair bit in the opposite direction. If a sort is any more complex than -n or -k<number no flags>, I tend to vipe¹ my sort in my editor. It feels great when you can use narrow-to-region² to perfect a complex address or write a custom function with all your editor's power at your fingertips. With the sad, but obvious, drawback that the changes aren't linked in your disjoint shell and editor history. ¹ https://manpages.debian.org/jessie/moreutils/vipe.1.en.html https://manpages.debian.org/jessie/moreutils/vipe.1.en.html ² Nowadays, that is more likely https://github.com/chrisbra/NrrwRgn https://github.com/chrisbra/NrrwRgn for me.
- deleted 3y ago
  [deleted]
- deleted 3y ago
  [deleted]
tom_ 3y ago
Org mode is recommended if you have tabular data, in case there are any Emacs users that still haven't tried it. (Which might sound ridiculous - but who knows? I still haven't used magit! I've been using Emacs since 2006.) You can sort the table using M-x org-table-sort-lines. (Org mode tables, while simple plain text, are very readable. Anybody not using Emacs is going to find them tedious to edit though.)
- drunkpotato 3y ago
  org-mode tables are great. So is magit, I highly recommend it! I'm comfortable with command line git, use it quite a lot, but I also use magit a lot, and magit is especially great as a much better `git add -p`.
  - mbork_pl 3y ago
    > org-mode tables are great True, though they tend not to be very fast when they grow. (I have a table with almost 2000 rows and editing it lags a bit.)
    - zelphirkalt 3y ago
      I found that keeping tables narrow (not too many characters per line) helps. I try to build my tables so that most of the logic (I do spreadsheets with them) is oriented towards more rows instead of more columns. However, I've not had 2000 lines tables yet. Perhaps a good trick is to divide them into multiple ones? Perhaps one for each category of things, if you have any different categories.
  - kqr 3y ago
    If anything, magit made me more comfortable with command line Git, by helping me discover things (--force-with-lease) and grok concepts (history editing) that I otherwise would not learn as quickly.
  - pxc 3y ago
    > magit is especially great as a much better `git add -p`. In Git, except for when adding new files, I always use `git add -p` to stage changes. And it's definitely the number one thing I do with Magic in terms of frequency. I can confirm that if you're an `add -p` kinda person, you'll love Magit.
msravi 3y ago
In vim, :%!sort... does the trick.
sshaw 3y ago
Sorting in Emacs, with my setup? I'm going to keep my fingers on the C-g keys...

152 points by susam 3y ago

I often want to sort within a line: [“zoo”, “cow”] Would become [“cow”, “zoo”] Any tips on how to do that? Ideally using just built in functions… I usually insert newlines between the elements, use a line-based sort, then recombine the lines. That works but is more tedious than I’d like. I’ve never taken the time to wrap that logic it in a function because it’s infrequent and it seems like it’s always slightly different.

G3rn0ti 3y ago
Keyboard macro. You convert the arrays into lines, you sort the result and then turn them back into arrays. If you do this often you could store the macro as an interactive command.
- agumonkey 3y ago
  and for larger lists maybe a C-u shell-command-on-region to a script
deleted 3y ago
[deleted]
pasc1878 3y ago
Why bother recombining the lines?
- CanaryLayout 3y ago
  Mostly to pretty it back up into the original shape (so it matches what was already in git)
  - pasc1878 3y ago
    Take one hit on format - your change is also only a format change.
kroger 3y ago
I found this on the Emacs Wiki [1]. It seems to work: (defun sort-symbols (reverse beg end) "Sort symbols in region alphabetically, in REVERSE if negative. See `sort-words'." (interactive "*P\nr") (sort-regexp-fields reverse "\\(\\sw\\|\\s_\\)+" "\\&" beg end)) [1]: https://www.emacswiki.org/emacs/SortWords https://www.emacswiki.org/emacs/SortWords
tom_ 3y ago
Copy to clipboard, paste into your interactive Python window, and use as the argument to sorted. Copy and paste the interpreter's output back into your code.
- owl57 3y ago
  You technically described how to make a word sorting macro execute arbitrary code. Fascinating to think how that doesn't mean it's bad advice. That is, unless your threat model includes targeted attacks by three-letter-scale adversaries — and then you maybe just don't open untrusted files in Emacs or use advice from strangers on HN.
  - tom_ 3y ago
    That's a good point. My assumption, not that I ever stated it, was that the list would be one you'd typed out yourself, or was one that was just there in code already, and you could verify by eye that it's just string literals. Using Python's eval with empty globals and locals dicts (consult the docs) could make this safer, though I've only ever had to use that for defending against accidents rather than malice. And now this quick thing is becoming increasingly complicated, and maybe you'd be better off engineering it properly.
  - ktm5j 3y ago
    This is actually a rather common thing to do.. I have functions that run shell commands in my spacemacs config to do things like this. For example I've got one that runs `date` to insert today's date in a particular format.
- deleted 3y ago
  [deleted]
- lvass 3y ago
  >Copy to clipboard, paste into your interactive Python window python-shell-send-statement, it's built into Emacs's python mode.
  - 3y ago
brunoqc 3y ago
http://yummymelon.com/devnull/moving-text-elegantly-in-emacs.html http://yummymelon.com/devnull/moving-text-elegantly-in-emacs... maybe
natrys 3y ago
Probably simplest is to not overthink and just write elisp, which is a fairly normal language. (defun my-sort-list () (interactive) (when (not (looking-at (rx "["))) (search-backward "[" nil t)) (when-let* ((line (thing-at-point 'sexp t)) (items (split-string (substring line 1 -1) (rx ",") t (rx blank))) (sorted (string-join (sort items #'string-lessp) ", "))) (kill-sexp) (insert "[" sorted "]"))) I don't think I am using any non-builtin function here, though I think a few exceptions like s.el, f.el and dash.el can make things much easier.
- minhm 3y ago
  "split-string" works well for this situation but for a case where there are commas inside some of the strings it would chop in the middle of those strings. So for the latter case and assuming the commas are consistently formatted, a safer approach might be starting in front of the first s-expression and then traversing to the tail of each s-expression with "forward-sexp" and check to see if a comma is there as expected and then delete the comma there (except for the last item with no comma) .
  - natrys 3y ago
    Yeah that's the classic comma in CSV problem. The solution is to indeed use a proper grammar/parser. The "forward-sexp" understands that as per major-mode rule as you say. Another more modern and declarative solution would be to take advantage of the full parse tree at your disposal thanks to tree-sitter (available in Emacs 29.1). Then you can simply do: (let ((list (treesit-thing-at-point "list" 'nested)) (query "(list (string (string_content) @item))")) (cl-loop for (_ . item) in (treesit-query-capture list query) collect (treesit-node-text item t)))
deleted 3y ago
[deleted]
gnuvince 3y ago
Select the line, then type C-u M-| jq -c sort
- gumby 3y ago
  I've been using Emacs for over 40 years but still find the shell my go-to sorting approach. Right tool for the job and all that.
  - JNRowe 3y ago
    I lean a fair bit in the opposite direction. If a sort is any more complex than -n or -k<number no flags>, I tend to vipe¹ my sort in my editor. It feels great when you can use narrow-to-region² to perfect a complex address or write a custom function with all your editor's power at your fingertips. With the sad, but obvious, drawback that the changes aren't linked in your disjoint shell and editor history. ¹ https://manpages.debian.org/jessie/moreutils/vipe.1.en.html https://manpages.debian.org/jessie/moreutils/vipe.1.en.html ² Nowadays, that is more likely https://github.com/chrisbra/NrrwRgn https://github.com/chrisbra/NrrwRgn for me.
deleted 3y ago
[deleted]
deleted 3y ago
[deleted]

tom_ 3y ago

Org mode is recommended if you have tabular data, in case there are any Emacs users that still haven't tried it. (Which might sound ridiculous - but who knows? I still haven't used magit! I've been using Emacs since 2006.) You can sort the table using M-x org-table-sort-lines. (Org mode tables, while simple plain text, are very readable. Anybody not using Emacs is going to find them tedious to edit though.)

drunkpotato 3y ago
org-mode tables are great. So is magit, I highly recommend it! I'm comfortable with command line git, use it quite a lot, but I also use magit a lot, and magit is especially great as a much better `git add -p`.
- mbork_pl 3y ago
  > org-mode tables are great True, though they tend not to be very fast when they grow. (I have a table with almost 2000 rows and editing it lags a bit.)
  - zelphirkalt 3y ago
    I found that keeping tables narrow (not too many characters per line) helps. I try to build my tables so that most of the logic (I do spreadsheets with them) is oriented towards more rows instead of more columns. However, I've not had 2000 lines tables yet. Perhaps a good trick is to divide them into multiple ones? Perhaps one for each category of things, if you have any different categories.
- kqr 3y ago
  If anything, magit made me more comfortable with command line Git, by helping me discover things (--force-with-lease) and grok concepts (history editing) that I otherwise would not learn as quickly.
- pxc 3y ago
  > magit is especially great as a much better `git add -p`. In Git, except for when adding new files, I always use `git add -p` to stage changes. And it's definitely the number one thing I do with Magic in terms of frequency. I can confirm that if you're an `add -p` kinda person, you'll love Magit.

msravi 3y ago

In vim, :%!sort... does the trick.

sshaw 3y ago

Sorting in Emacs, with my setup? I'm going to keep my fingers on the C-g keys...