Groovy 3 was released a few days ago[1], and it introduced a lot of important new features to the language. Today I want to show you a few useful improvements in the GDK. We will take a closer look into methods like takeRight, takeAfter, takeBetween, and a few others that were added to the java.lang.String class.
In this blog post we use String as a base class, but most (if not all) of presented methods are working with String, CharSequence and GString classes. |
String.takeRight(int)
Let’s start with the first one - takeRight. This method allows you to extract n last characters from a given String (or all characters if the number is larger then the string length.)
final String text = "Groovy"
assert text.takeRight(0) == ""
assert text.takeRight(1) == "y"
assert text.takeRight(3) == "ovy"
assert text.takeRight(20) == "Groovy"String.takeAfter(str)
This method allows you to extract the text that exists after the first occurrence of the str. Keep in mind that it is case-sensitive, so it looks for the exact match.
final String text = "Groovy"
assert text.takeAfter("G") == "roovy"
assert text.takeAfter("g") == ""
assert text.takeAfter("Gro") == "ovy"
assert text.takeAfter("Groovy") == ""String.takeBefore(str)
It is similar to takeAfter, but here it extracts the text that exists before the first occurrence of str.
final String text = "Groovy"
assert text.takeBefore("G") == ""
assert text.takeBefore("g") == ""
assert text.takeBefore("ovy") == "Gro"
assert text.takeBefore("o") == "Gr"
assert text.takeBefore("Groovy") == ""String.takeBetween(from,to)
This method allows you to extract the text that exists between the first occurrence of from and to. It can be used with a single parameter, then to becomes from. There is also a third optional parameter - occurrence which defines which occurrence should be taken into account (default: the first occurrence of from and to).
final String text = "Lorem ipsum dolor sit amet"
assert text.takeBetween("i") == "psum dolor s"
assert text.takeBetween("i", "r") == "psum dolo"
assert text.takeBetween("i", "a") == "psum dolor sit "
assert text.takeBetween("l","o") == ""
assert text.takeBetween("m") == " ipsu"
assert text.takeBetween("m", 1) == ""
assert text.takeBetween("i", "m", 0) == "psu"
assert text.takeBetween("i", "m", 1) == "t a"
assert text.takeBetween("i", "m", 2) == ""String.dropRight(int)
This is an equivalent of String.drop(int) method, but in this case it produces a new String that drops n characters from the right side.
final String text = "Hello, World!"
assert text.dropRight(4) == "Hello, Wo"
assert text.dropRight(0) == "Hello, World!"
assert text.dropRight(-10) == "Hello, World!"
assert text.dropRight(20) == ""String.startsWithIgnoreCase(str) and similar
Groovy also adds "ignore case" variants to three popular String methods:
String.startsWithIgnoreCase(str)String.endsWithIgnoreCase(str)String.containsIgnoreCase(str)
final String text = "Hello, World!"
assert text.startsWithIgnoreCase("he") == true
assert text.startsWithIgnoreCase("HE") == true
assert text.startsWithIgnoreCase("HEE") == false
assert text.endsWithIgnoreCase("D!") == true
assert text.endsWithIgnoreCase("LD!") == true
assert text.endsWithIgnoreCase("LLD!") == false
assert text.containsIgnoreCase("HELL") == true
assert text.containsIgnoreCase("OLD") == false
assert text.containsIgnoreCase("OrLd") == trueGroovy 3 Quick Review | #groovylang
In this video, I check what features are added in the recent Groovy 3 release.
Thank you!
Thank you so much for reading up to this point! I hope this article met your expectations, and you have learned something valuable from it. If you have one more minute, leave me a comment below, please. This way, I can thank you for your time more in person.
And last but not least. If you find this blog post valuable, help me spread the word, please. You can share it on Twitter, LinkedIn, or anywhere else you can think of. This single tweet or post on social media helps a lot. One more time - thank you so much! You’re awesome!
(PS: Check "Related posts" below for more content like this one.)
