How to create a string list in Clojure?

Question

I want to create a string list in Clojure equivalent to the following Java code:

List<String> cities = Arrays.asList(new String[] {"Berlin", "Brussels", "Helsinki", "Madrid", "Oslo", "Paris","Stockholm" });

: but I am unsure about the exact syntax

As a side note at least in newer Java versions you can just use Arrays.asList("Berlin", "Brussels", "Helsinki", "Madrid", "Oslo", "Paris", "Stockholm"). — ponzao
– ponzao, Commented Feb 23, 2011 at 8:43
possible duplicate of Converting Clojure data structures to Java collections — Alex Baranosky
– Alex Baranosky, Commented Aug 11, 2012 at 9:23
for all those interested in Clojure. In Clojure, the list does not provide direct access, for direct access you need Vector (in Clojure). — Mr.Q
– Mr.Q, Commented Mar 2, 2019 at 17:24

aav · Accepted Answer · 2011-02-22 20:47:16Z

17

Strictly speaking, examples provided above will produce vectors. List can be produced in the following way:

(list "Berlin", "Brussels", "Helsinki", "Madrid", "Oslo", "Paris","Stockholm")

or shorter:

'("Berlin", "Brussels", "Helsinki", "Madrid", "Oslo", "Paris","Stockholm")

In some cases this difference could be important.

answered Feb 22, 2011 at 20:47

aav

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1 Comment

Arthur Ulfeldt Over a year ago

the tick in front will also prevent anything in the list from being evaluated. its good to be aware of the difference between <code>(list "hello" (str "hello " "world") "world") ==> "hello hello world world"</code> and '("hello" (str "hello " "world") "world") produces its seld with the (str "hello" "world") intact

Steve Kuo · Accepted Answer · 2012-07-18 17:35:19Z

8

(def cities ["Berlin" "Brussels" "Helsinki" "Madrid" "Oslo" "Paris" "Stockholm"])

http://en.wikibooks.org/wiki/Clojure_Programming/Tutorials_and_Tips#Clojure_for_Java_Programmers

edited Jul 18, 2012 at 17:35

Steve Kuo

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answered Feb 22, 2011 at 17:23

Matt Ball

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Comments

Arthur Ulfeldt · Accepted Answer · 2011-02-26 21:40:31Z

in general you can use the name of a collection you want to create as the function to create it (easy to remember eh?):

(vector     "Berlin", "Brussels", "Helsinki", "Madrid", "Oslo", "Paris","Stockholm")
(hash-map   "Berlin", "Brussels", "Helsinki", "Madrid", "Oslo", "Paris")
(sorted-map "Berlin", "Brussels", "Helsinki", "Madrid", "Oslo", "Paris")
(array-map  "Berlin", "Brussels", "Helsinki", "Madrid", "Oslo", "Paris")
(hash-set   "Berlin", "Brussels", "Helsinki", "Madrid", "Oslo", "Paris" "Stockholm")
(sorted-set "Berlin", "Brussels", "Helsinki", "Madrid", "Oslo", "Paris" "Stockholm")

or you can use into if you dont know in advance what type you will need to create.

(defn make-trip [trip cities]
    (into trip cities))

and pass it something like (make-trip #{"home"} ["Berlin", "Brussels", "Helsinki", "Madrid", "Oslo", "Paris"])

Alex Baranosky · Accepted Answer · 2012-08-11 09:22:40Z

4

None of these are actually equivalent to:

List<String> cities = Arrays.asList(new String[] {"Berlin", "Brussels", "Helsinki", "Madrid", "Oslo", "Paris","Stockholm" });

This is much closer to an answer to what was actually asked:

user=> (java.util.ArrayList. [1 2 3])
#<ArrayList [1, 2, 3]>
user=> (.get (java.util.ArrayList. [1 2 3]) 0)
1

answered Aug 11, 2012 at 9:22

Alex Baranosky

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Comments

Nathan Hughes · Accepted Answer · 2011-02-22 17:23:31Z

2

How about:

(def cities ["Berlin", "Brussels", "Helsinki", "Madrid", "Oslo", "Paris","Stockholm"])

The commas are optional.

answered Feb 22, 2011 at 17:23

Nathan Hughes

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