Regex to match may keys taht contain ($)

Question

Method to filter Map where regex ($) is matched :

public Map getVariables(Map<String , String> nvp){

        Map map = nvp.entrySet().parallelStream()
                .filter(e -> e.getKey().matches("(($.*?))"))
                .collect(Collectors.toMap(Map.Entry::getKey, Map.Entry::getValue));

        return map;

    }

Setup a map that contains key/value "($test)", "test value" :

private Map<String , String> nvp = new HashMap<String , String>();
public void setup(){
    nvp.put("($test)", "test value");
}

Add a method to test that "($test)" is contained in the Map returned :

public void testGetVariables(){

    OpDocVariableInsert o = new OpDocVariableInsert();
    System.out.println(o.getVariables(nvp).size());
}

But 0 results are returned. I think my regex is incorrect ?

`$` has a special meaning in regex, you should escape it: `\\$`. Also note that you should escape the `(` and `)` if you didn't mean to capture the match. — Maroun, Mar 16 '16 at 15:03
Note `\$\\$[^)]++\$` would be a more efficient pattern than using a lazy `.`. — Boris the Spider, Mar 16 '16 at 15:07

score 2 · Accepted Answer · answered Mar 16 '16 at 15:04

2

$ and () have special meanings in regex and should be escaped to match their original characters :

\\(\\$.*?\\)

answered Mar 16 '16 at 15:04

Aaron

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Or using the fancy `Pattern.quote`. – Maroun Mar 16 '16 at 15:05
1

@MarounMaroun my first thought too - wouldn't work all-at-once because of the `.*?`. Using two `Pattern.quote` and concatting seems a little ugly... – Boris the Spider Mar 16 '16 at 15:06
@BoristheSpider Missed that.. sure, in this case quoting is better. – Maroun Mar 16 '16 at 15:07

Regex to match may keys taht contain ($)

1 Answers1