Convert String variable to a List [Groovy]

Question

How can I convert this String variable to a List ?

def ids = "[10, 1, 9]"

I tried with: as List and toList();

But when I do ids.each{println it} I have this result : [ 1 0 , 1 ] — user2068981, Feb 28 '13 at 00:15

score 35 · Accepted Answer · answered Feb 28 '13 at 20:20

35

def l = Eval.me(ids)

Takes the string of groovy code (in this case "[10,1,9]") and evaluates it as groovy. This will give you a list of 3 ints.

answered Feb 28 '13 at 20:20

Rick Mangi

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http://www.jameswiseman.com/blog/2011/01/18/jslint-messages-eval-is-evil/ – Alexander Suraphel Feb 23 '17 at 06:44
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@AlexanderSuraphel Wrong language. – chrylis -cautiouslyoptimistic- Aug 27 '18 at 05:04
@chrylis Meaning? – Alexander Suraphel Aug 31 '18 at 14:54
@AlexanderSuraphel I will answer for him: your article is related to JavaScript (JSLint specifically). But question itself was about Groovy. – Michael A. Jan 13 '19 at 09:46
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@MichaelA. Have you read the linked articles? The problem is not specific to JavaScript's Eval. It's the idea of passing a string to a method that is willing to execute anything. I felt that OP needs to know the risks as well. – Alexander Suraphel Jan 14 '19 at 08:26
I think a better link is https://stackoverflow.com/questions/86513/why-is-using-the-javascript-eval-function-a-bad-idea. The ideas discussed apply to any language, not just JavaScript. – Alexander Suraphel Jan 14 '19 at 08:29
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I would not consider using Eval as a safe option though. – Pavol Travnik Feb 28 '20 at 15:34

score 30 · Answer 2 · edited Mar 09 '13 at 03:05

30

def l = ids.split(',').collect{it as int}

edited Mar 09 '13 at 03:05

animuson

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answered Feb 28 '13 at 00:10

Sergio Martinez

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I think you want to make a string "10,1,9" into a list [10,1,9] – Sergio Martinez Feb 28 '13 at 00:17
def id = ids.substring(1,ids.length()-1) def l= id.split(',').collect{it as int} – user2068981 Feb 28 '13 at 00:44
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I find this solution but I don't think is the best : def id = ids.substring(1,ids.length()-1) def l= id.split(',').collect{it as int} – user2068981 Feb 28 '13 at 00:48
this works great for me, specifically in Jenkins, and using String instead of Int: `files = "'f1','f2'" list = files.split(',').collect{it as String} > list==['f1', 'f2'] > list[1]=='f2' ` – Max Cascone Nov 10 '20 at 20:28
updating mine after the edit window closed: `list = versionFile.split(',').collect()` works fine for strings. – Max Cascone Nov 10 '20 at 20:38

Alexander Suraphel · Answer 3 · 2022-10-13T13:27:30.933

30

Use the built-in JsonSlurper!

Using Eval could be risky as it executes any code and the string manipulation solution will fail once the data type is changed so it is not adaptable. So it's best to use JsonSlurper.

import groovy.json.JsonSlurper

//List of ints 
def ids = "[10, 1, 9]"
def idList = new JsonSlurper().parseText(ids)

assert 10 == idList[0]

//List of strings 
def ids = '["10", "1", "9"]'
idList = new JsonSlurper().parseText(ids)

assert '10' == idList[0]

edited Oct 13 '22 at 13:27

answered Apr 16 '15 at 12:41

Alexander Suraphel

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This should definitely be accepted as right answer. – Pavol Travnik Feb 28 '20 at 15:40
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For me with strings this only works when I have : '["string1", "string2"]' and not with "['string1', 'string2']" running the code from jenkins. – herm Nov 22 '21 at 15:01
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@herm tested it myself and you're right. i've updated the answer – Alexander Suraphel Nov 23 '21 at 08:20

score 14 · Answer 4 · answered Mar 23 '19 at 04:56

14

This does work for me. And Eval.me will not work in Jenkins groovy script. I have tried.

assert "[a,b,c]".tokenize(',[]') == [a,b,c]

answered Mar 23 '19 at 04:56

TangHongWan

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`Eval.me` didn't work for me as well (Jenkins groovy script). However, your solution gave a wrong result. My str is "['/a/b/c/d@2/e/f/g/h/i/j/k/l.py::m[n-10-3-9-0/8-17-12]',]" (actually I have more entries in the string, but this is the general idea). The tokenize returns only the inner list, i.e. "[n-10-3-9-0/8-17-12]'" – CIsForCookies Sep 19 '19 at 12:12
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The higher scoring answers didn't work for me. This one did. – Vladimir Oct 21 '19 at 13:44
Could you explain what exactly tokenize(',[]') doing here? – Raunak Kapoor Aug 25 '22 at 20:37
Without the brackets, you get [[a, b, c]] as a result. Not sure I understand how adding the brackets removes the additional outer list. – Nick Apr 11 '23 at 21:00

Convert String variable to a List [Groovy]

4 Answers4