clojure.core/meta

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Type: function Added: Clojure 1.0 Examples: 3 Runnable: 0

([obj])

Returns the metadata of obj, returns nil if there is no metadata.

Examples

by devn on 2010-08-02 . May have evaluation errors. ▶

(use 'clojure.pprint) (pprint (meta #'first)) ;;=> prints the following... {:ns #<Namespace clojure.core>, :name first, :added "1.0", :file "clojure/core.clj", :static true, :column 1, :line 49, :arglists ([coll]), :doc "Returns the first item in the collection. Calls seq on its\n argument. If coll is nil, returns nil."}

by finalfantasia on 2018-02-26 . May have evaluation errors. ▶

;; attach metadata to s. ;; ^:private is a shorthand notation for ^{:private true} and ;; ^String is a shorthand notation for ^{:tag java.lang.String}. (def ^:private ^String s "Hello, world!") ;; inspect the metadata attached to s. ;; note, you need to use the var #'s, instead of the symbol s, as the argument. (clojure.pprint/pprint (meta #'s)) ;; => {:private true, :tag java.lang.String, :line 3, :column 1, :file "/tmp/form-init5430922801479403331.clj", :name s, :ns #object[clojure.lang.Namespace 0x13fca031 "user"]}

by randomizedthinking on 2022-12-12 . May have evaluation errors. ▶

;; attach metadata to var x (def ^{:version 1} x [1 2 3]) ;; retrieve metadata of var x: note the notation (meta #'x) ;; => {:version 1, :line 3, :column 1, :file "...", :name x, :ns ...} ;; attach metadata to an obj (def y ^{:version 1} [1 2 3]) (meta y) ;=> {:version 1}

See also

• clojure.core/with-meta (1)
• clojure.core/*print-meta* (1)
• clojure.core/vary-meta (1)

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