clojure.core/read-string

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Type: function Added: Clojure 1.0 Examples: 11 Runnable: 4

([s] [opts s])

Reads one object from the string s. Optionally include reader options, as specified in read.

Note that read-string can execute code (controlled by read-eval), and as such should be used only with trusted sources.

For data structure interop use clojure.edn/read-string

Examples

by gstamp on 2010-08-24 . May have evaluation errors. ▶

(read-string "1.1") 1.1 (read-string "1.1.1 (+ 1 1)") java.lang.RuntimeException: java.lang.NumberFormatException: Invalid number: 1.1.1 (NO_SOURCE_FILE:0) (read-string "(+ 1 1)") (+ 1 1)

by boxie on 2010-11-10 ▶

(eval (read-string "(+ 1 1)")) 2 (read-string (prn-str (+ 1 1))) 2

by benjiiiiii on 2010-12-01 ▶

(+ 11 (read-string "23")) 34

by devn on 2012-04-26 . May have evaluation errors. ▶

(read-string "; foo\n5") 5 (read-string "#^String x") x (read-string "(1)") (1) (read-string "(+ 1 2) (- 3 2)") (+ 1 2) (read-string "@a") (clojure.core/deref a) (read-string "(+ 1 2))))))") (+ 1 2) (read-string "::whatever-namespace-you-are-in") :user/whatever-namespace-you-are-in

by dansalmo on 2012-08-21 . May have evaluation errors. ▶

;convert a string representing a sequence, ;to the sequence that the string represents (read-string "(\\( \\x \\y \\) \\z)") (\( \x \y \) \z) ;then you can convert to the string that the string-sequence represents (apply str (read-string "(\\( \\x \\y \\) \\z)")) "(xy)z" ;which is the inverse of (str (first (list (seq "(xy)z")))) "(\\( \\x \\y \\) \\z)"

by dansalmo on 2012-09-05 . May have evaluation errors. ▶

;; you can think of read-string as the inverse of pr-str ;; turn string into symbols (read-string "(a b foo :bar)") (a b foo :bar) ;;turn symbols into a string (pr-str '(a b foo :bar)) "(a b foo :bar)"

by jafingerhut on 2013-02-12 ▶

;; WARNING: You SHOULD NOT use clojure.core/read-string to read data from ;; untrusted sources. See the examples for clojure.core/read, because the same ;; issues exist for both read and read-string.

by one-finger on 2016-02-20 ▶

;; convert binary number provided in the form of a string to its numerical value. (read-string (str "2r" "1011")) 11

by loeschzwerg on 2019-05-05 . May have evaluation errors. ▶

;; be careful with octal values (read-string "042") 34 (read-string "08") Execution error (NumberFormatException) Invalid number: 08 ;; replace leading zeroes with regex (read-string (clojure.string/replace "042" #"^0+(?!$)" "")) 42 (read-string (clojure.string/replace "00" #"^0+(?!$)" "")) 0

by adanhawth on 2020-02-26 . May have evaluation errors. ▶

;; if someone littered your csv fields with escaped double quotes... (def quoted-string "\"1.23\"") ;; and you find yourself in angst, cause this won't work... (Double. quoted-string) ;; Execution error (IllegalArgumentException) at user/eval6365 (form-init17453115089215840832.clj:1). ;; No matching ctor found for class java.lang.Double ;; you don't have to hate the player; but you can come prepared for the game (Double. (read-string quoted-string)) ;; 1.23

by ertugrulcetin on 2022-08-17 . May have evaluation errors. ▶

;;;; Data representation is same as the one produced by (read-string) ;;;; and (read) when provided with the option to preserve data conditionals (read-string {:read-cond :preserve} "#?(:clj (println \"Hey World!\"))") ;;=> #?(:clj (println "Hey World!"))

Note by boxie

read-string is useful for running clojure code from a script or translator.

Note by bfontaine

Never EVER use read-string on data from an untrusted source. Prefer clojure.edn/read-string to parse EDN. The former can execute arbitrary code, including calling external URLs or reading/writing/erasing files.

See also

• clojure.core/pr-str (3)
• clojure.core/str (7)
• clojure.core/read (0)
• clojure.core/load-string (0)
• clojure.core/*read-eval*
• clojure.main/load-script
• clojure.edn/read-string (0)

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Content from the matching ClojureDocs page, with authors credited on each contribution.