Convert String to arrayList in groovy

Question

I have a string like: String str = "[aa,bb,cc,dd]". I want to convert this to a list in groovy like [aa, bb, cc, dd]. Any groovy method available for this type conversion?

In case you got this string because you do an (accidental) toString on a "real" list, you are better off preventing that. This is an accident to happen otherwise: ["1,2"].toString() => [1,2] — cfrick
– cfrick, Commented Jul 18, 2016 at 16:07
I need to store a list in database also return that as list ,can you give me better solution. — Sayem
– Sayem, Commented Jul 18, 2016 at 16:30
Use a format, that is made to (de)serialize data and pick one, that is able to hold the data type you want. E.g. for a List<String> you can use JSON. Or since you are on Grails already, why not make it a List<String> on a GORM class and just store it as what it is. — cfrick
– cfrick, Commented Jul 19, 2016 at 6:15

Gergely Toth · Accepted Answer · 2016-07-18 14:32:13Z

9

Using regexp replaceAll

String str = "[aa,bb,cc,dd]"
def a = str.replaceAll(~/^\[|\]$/, '').split(',')
assert a == ['aa', 'bb', 'cc', 'dd']

EDIT:

The following version is a bit more verbose but handles extra white spaces

String str = " [ aa , bb , cc , dd ] "
def a = str.trim().replaceAll(~/^\[|\]$/, '').split(',').collect{ it.trim()}
assert a == ['aa', 'bb', 'cc', 'dd']

edited Jul 18, 2016 at 14:32

answered Jul 18, 2016 at 13:24

Gergely Toth

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Saurabh Gaur · Accepted Answer · 2016-07-18 13:05:10Z

6

You should try as below :-

String str = "[aa,bb,cc,dd]"
assert str[1..str.length()-2].tokenize(',') == ['aa', 'bb', 'cc', 'dd']

Hope it helps..:)

answered Jul 18, 2016 at 13:05

Saurabh Gaur

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2 Comments

railsdog Over a year ago

Perhaps simplify a bit: tokenize('[,]')

Gergely Toth Over a year ago

str[1..str.lenght()-2] can be simplified to str[1..-2]

Opal · Accepted Answer · 2016-07-18 12:59:30Z

2

Here you go:

String str= "['aa', 'bb', 'cc', 'dd']"
assert Eval.me(str) == ['aa', 'bb', 'cc', 'dd']

Eval is what you need.

answered Jul 18, 2016 at 12:59

Opal

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2 Comments

Jérémie B Over a year ago

If this string come from an external system, or a user, it's not really secure to use Eval for this. I prefer to use a real parser/regex for this than eval

Opal Over a year ago

@JérémieB, yes you're right, in such scenario it's much better to use regex.

injecteer · Accepted Answer · 2016-07-18 14:51:14Z

0

another way w/o replaceAll & tokenize:

def s = '[aa,bb,cc,dd]'
def a = []
s.eachMatch( /[\[]?([^\[\],]+)[,\]]?/ ){ a << it[ 1 ] }
assert '[aa, bb, cc, dd]' == a.toString()

answered Jul 18, 2016 at 14:51

injecteer

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