how to remove whitespace at the beginning of each element of a Strings array

Question

I have an array such as def list = ["pathfinding", " Gameplay", "Community"] which I would like to iterate and eliminate the whitespace at the beginning of each element. So I though it would be easy using something like:

for(x in list){
    x = x.replace("\\s", "")
    println x
}

but I keep getting this output

pathfinding
    Gameplay
Community

I do now know much about regex what I tried different ones I found here in SO and none worked so I guess the regex is not the problem here... any hints?

Groovy has method "".trim() if I remember correctly so you don't need to mess with regex. — Tarmo
– Tarmo, Commented Apr 27, 2021 at 18:23

tim_yates · Accepted Answer · 2021-04-27 19:22:52Z

6

Or you can just trim all the elements in the list

def trimmedList = list*.trim()

answered Apr 27, 2021 at 19:22

tim_yates

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xjcl · Accepted Answer · 2021-04-27 19:23:46Z

1

Using replaceAll instead of replace works:

for (x in list) {     
    x = x.replaceAll("\\s", "")     
    println x
}

answered Apr 27, 2021 at 19:23

xjcl

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matthew · Accepted Answer · 2021-04-27 18:24:43Z

0

you can use String#trim()

def list = ["pathfinding", "    Gameplay", "Community"]
for(x in list){
    x = x.trim()
    log(x)
}

answered Apr 27, 2021 at 18:24

matthew

1

Comments

Matthew · Accepted Answer · 2021-04-27 18:53:04Z

This is how I would trim leading space in Java:

public String trimLeadingWhitespace(String text) {

    Matcher matcher = PATTERN.matcher(text);
    if (matcher.find()) {
        return matcher.group(1);
    }
    else throw new RuntimeException("Unable to match pattern");
}

I am using regex to match the whitespace characters.

You can test the above code like this:

@Test
void shouldTrimLeadingWhitespace() {

    String[] array = new String[] { " pathfinding", "    Gameplay", "   Community" };
    for (String entry : array)
    {
        Assertions.assertTrue(entry.startsWith(" "));

        String trimmed = trimLeadingWhitespace(entry);
        Assertions.assertFalse(trimmed.startsWith("\\s"));

        System.out.println("Trimmed entry: " + trimmed);
    }
}

Matias Bjarland · Accepted Answer · 2021-04-28 07:13:01Z

0

If you only want to trim the beginning and not the end, this is also a way:

def clean = list.collect { it.dropWhile { it == ' ' } }

running:

def list = ["pathfinding", "    Gameplay", "Community"]
def clean = list.collect { it.dropWhile { it == ' ' } }
println clean

prints:

─➤ groovy solution.groovy
[pathfinding, Gameplay, Community]

─➤

edited Apr 28, 2021 at 7:13

answered Apr 27, 2021 at 21:13

Matias Bjarland

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