From 82ba818ff456bcd6d56a06226e3f27e98fbb55c3 Mon Sep 17 00:00:00 2001 From: Craig Jennings Date: Thu, 14 Aug 2025 22:58:58 -0500 Subject: removing all downloaded devdocs files --- devdocs/elisp/mapping-functions.html | 62 ------------------------------------ 1 file changed, 62 deletions(-) delete mode 100644 devdocs/elisp/mapping-functions.html (limited to 'devdocs/elisp/mapping-functions.html') diff --git a/devdocs/elisp/mapping-functions.html b/devdocs/elisp/mapping-functions.html deleted file mode 100644 index 2f920180..00000000 --- a/devdocs/elisp/mapping-functions.html +++ /dev/null @@ -1,62 +0,0 @@ -

Mapping Functions

A mapping function applies a given function (not a special form or macro) to each element of a list or other collection. Emacs Lisp has several such functions; this section describes mapcar, mapc, mapconcat, and mapcan, which map over a list. See Definition of mapatoms, for the function mapatoms which maps over the symbols in an obarray. See Definition of maphash, for the function maphash which maps over key/value associations in a hash table.

These mapping functions do not allow char-tables because a char-table is a sparse array whose nominal range of indices is very large. To map over a char-table in a way that deals properly with its sparse nature, use the function map-char-table (see Char-Tables).

Function: mapcar function sequence -
-

mapcar applies function to each element of sequence in turn, and returns a list of the results.

The argument sequence can be any kind of sequence except a char-table; that is, a list, a vector, a bool-vector, or a string. The result is always a list. The length of the result is the same as the length of sequence. For example: 

(mapcar #'car '((a b) (c d) (e f)))
-     ⇒ (a c e)
-(mapcar #'1+ [1 2 3])
-     ⇒ (2 3 4)
-(mapcar #'string "abc")
-     ⇒ ("a" "b" "c")
-
- -
;; Call each function in my-hooks.
-(mapcar 'funcall my-hooks)
-
- -
(defun mapcar* (function &rest args)
-  "Apply FUNCTION to successive cars of all ARGS.
-Return the list of results."
-  ;; If no list is exhausted,
-  (if (not (memq nil args))
-      ;; apply function to CARs.
-      (cons (apply function (mapcar #'car args))
-            (apply #'mapcar* function
-                   ;; Recurse for rest of elements.
-                   (mapcar #'cdr args)))))
-
- -
(mapcar* #'cons '(a b c) '(1 2 3 4))
-     ⇒ ((a . 1) (b . 2) (c . 3))
-
-
-
Function: mapcan function sequence -
-

This function applies function to each element of sequence, like mapcar, but instead of collecting the results into a list, it returns a single list with all the elements of the results (which must be lists), by altering the results (using nconc; see Rearrangement). Like with mapcar, sequence can be of any type except a char-table. 

;; Contrast this:
-(mapcar #'list '(a b c d))
-     ⇒ ((a) (b) (c) (d))
-;; with this:
-(mapcan #'list '(a b c d))
-     ⇒ (a b c d)
-
-
-
Function: mapc function sequence -

mapc is like mapcar except that function is used for side-effects only—the values it returns are ignored, not collected into a list. mapc always returns sequence.

-
Function: mapconcat function sequence separator -
-

mapconcat applies function to each element of sequence; the results, which must be sequences of characters (strings, vectors, or lists), are concatenated into a single string return value. Between each pair of result sequences, mapconcat inserts the characters from separator, which also must be a string, or a vector or list of characters. See Sequences Arrays Vectors.

The argument function must be a function that can take one argument and returns a sequence of characters: a string, a vector, or a list. The argument sequence can be any kind of sequence except a char-table; that is, a list, a vector, a bool-vector, or a string. 

(mapconcat #'symbol-name
-           '(The cat in the hat)
-           " ")
-     ⇒ "The cat in the hat"
-
- -
(mapconcat (lambda (x) (format "%c" (1+ x)))
-           "HAL-8000"
-           "")
-     ⇒ "IBM.9111"
-
-
-
-

- Copyright © 1990-1996, 1998-2022 Free Software Foundation, Inc.
Licensed under the GNU GPL license.
- https://www.gnu.org/software/emacs/manual/html_node/elisp/Mapping-Functions.html -

-
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