Groovy - Strings and Regular Expressions

10. Strings and Regular Expressions

Strings in Groovy

Strings in Groovy are sequences of characters and are used to represent textual data. Groovy provides a rich set of features for working with strings, including string interpolation, concatenation, and manipulation.

Creating Strings:

You can create strings in Groovy using either single quotes '' ''or double quotes '" "'. Double-quoted strings support string interpolation, while single-quoted strings are plain literals.

def name = "Alice"
def greeting = 'Hello,'

def age = 30
def message = "My age is ${age}"

In this example, the 'message' string is created by interpolating the 'age' variable.

String Concatenation:

You can concatenate strings using the '+' operator or the 'concat()' method.

def firstName = "John"
def lastName = "Doe"
def fullName = firstName + " " + lastName

In this example, we concatenated 'firstName' and 'lastName' to create 'fullName'.

String Length:

You can find the length of a string using the 'length()'method.

def text = "Hello, World!"
def length = text.length()

def text = "Hello, World!"
def substring = text.substring(7, 12)

def text = "  Groovy Programming  "
def trimmed = text.trim()

def str1 = "apple"
def str2 = "orange"
def isEqual = str1 == str2

In this example, 'isEqual' will be set to 'false'.

Regular Expressions in Groovy

Regular expressions (regex) are powerful patterns used for searching, matching, and manipulating strings. Groovy supports regular expressions through the '=~' operator and various methods in the 'java.util.regex' package.

Pattern Matching:

You can use the '=~' operator to check if a string matches a regular expression pattern.

def text = "Hello, World!"
def pattern = /Hello,/
def isMatch = text =~ pattern

In this example, 'isMatch' will be set to 'true'because the pattern matches the string.

Pattern Searching:

The 'find()'method can be used to search for the first occurrence of a pattern in a string.

def text = "The quick brown fox jumps over the lazy dog."
def pattern = /brown/
def found = text.find(pattern)

def text = "The quick brown fox jumps over the lazy dog."
def pattern = /brown/
def replaced = text.replaceAll(pattern, "red")

def text = "Date: 2023-09-01"
def pattern = /Date: (\d{4}-\d{2}-\d{2})/
def match = text =~ pattern
def date = match[0][1]