Regular Expressions in Groovy
How to extract substring in Groovy? Ask Question. Asked 5 years, 8 months ago. Active 5 years, 8 months ago. Viewed 22k times. Active Oldest Votes. Will Will I get an error: no such property sub for class: org. IgorGanapolsky are you running it from a script? Will, how do i get only the say next number and not the trailing ones after that? I know i have to modify the index.
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Feedback on Q2 Community Roadmap. Technical site integration observational experiment live on Stack Overflow.Here are some suggestions for using regular expressions in Groovy. This page mainly focuses on documenting regular expressions in Groovy, however, those suggestions are applicable to any programming language that supports regular expressions such as Perl and Java.
It's important to document any regular expression, or "regex" for short, that is more than a trivial match. Documenting regexes is the key to making them understandable so they can be debugged and modified either by someone else or by you after you've had time to forget the details.
Having a sample of the input that the regular expression is being applied to look at right on screen is a great help in deciphering what the pattern is trying to match. This is best done in a block comment before the regular expression pattern is defined. The "? The extended match mode is enabled by a pattern match flag which allows white space and comments to be embedded into the pattern.
You can then describe, piece by piece, the parts of the regular expression without dumping those details into the already large header comment suggested above. Pattern match flags are discussed in more detail later in this document. In Groovy, this match flag is "? This is done in conjunction with Groovy "here" documents triple quotingwhich is handled somewhat differently than the "slashy" quoting used for regular expression patterns.
The three examples below are equivalent, but I've highlighted in red what is removed from the first, and colored green the new text in the second and third examples. What does the third example buy you?
Now newlines and comments can be included. The third example here document above can also be written:. While developing regular expressions, you will probably want to be able to easily test the result. An easy option is to add debugging lines The debugging lines can be controlled by a boolean flag to turn them on or off. For little development programs and snippets in the groovyConsole, this is easier than setting up logging. The example above can be expanded with a 'debugging' flag and debugging lines like this:.
You can see by the output above that most of the input is ignored because it doesn't meet the described pattern. For those entries that are split across two lines, it turns out that all the information we want is in the second line, which still meets the pattern criteria, and the first line is ignored for not matching.
The Java regular expression support includes many options modeled after Perl, which is one of the strongest regular expression parsing languages. Since Groovy gets its regular expression capability from Java which copied Perlwhat works in Java applies equally well to Groovy. Looking at the Java java. Pattern API we see that there is support for pattern match flags under the section called "Special constructs non-capturing.
The dark mode beta is finally here. Change your preferences any time. Stack Overflow for Teams is a private, secure spot for you and your coworkers to find and share information. However I keep getting a null pointer exception because the regex doesn't seem to be working, what would be the correct regex for "any peace of text", and how to collect it from a string?
However I worry that you are planning to parse xml with regular expressions. If this cdata is part of a larger valid xml document, better to use an xml parser.
Please, take into account that in case of regexp doesn't match then result will be equal to the source. Unlikely in case of. Learn more. Asked 6 years, 9 months ago. Active 5 months ago. Viewed 41k times. RicardoE RicardoE 1, 2 2 gold badges 16 16 silver badges 40 40 bronze badges. Active Oldest Votes. Its not for valid xml THank you very much! I'm new to Groovy. Can you please explain why we need to dereference the matcher with  in order to get a list of groups? Michael Y Michael Y 6 6 bronze badges.
Naeel Maqsudov Naeel Maqsudov 8 8 silver badges 18 18 bronze badges. Sign up or log in Sign up using Google. Sign up using Facebook. Sign up using Email and Password. Post as a guest Name. Email Required, but never shown. The Overflow Blog. Socializing with co-workers while social distancing. Podcast Programming tutorials can be a real drag.
Featured on Meta. Community and Moderator guidelines for escalating issues via new response….02 - Regular Expressions ( [^] + * \w \d \s \b )
Feedback on Q2 Community Roadmap. Technical site integration observational experiment live on Stack Overflow. Triage needs to be fixed urgently, and users need to be notified upon…. Dark Mode Beta - help us root out low-contrast and un-converted bits.This chapter covers the syntax of the Groovy programming language. The grammar of the language derives from the Java grammar, but enhances it with specific constructs for Groovy, and allows certain simplifications.
Multiline comments can thus be put at the end of a statement, or even inside a statement. Those comments are associated with:. Although the compiler will not complain about Groovydoc comments not being associated with the above language elements, you should prepend those constructs with the comment right before it. In addition, Groovy supports Runtime Groovydoc since 3. Groovydoc can be retained at runtime. Beside the single-line comment, there is a special line comment, often called the shebang line understood by UNIX systems which allows scripts to be run directly from the command-line, provided you have installed the Groovy distribution and the groovy command is available on the PATH.
Quoted identifiers appear after the dot of a dotted expression.
For instance, the name part of the person. This is particularly interesting when certain identifiers contain illegal characters that are forbidden by the Java Language Specification, but which are allowed by Groovy when quoted. For example, characters like a dash, a space, an exclamation mark, etc.
As we shall see in the following section on stringsGroovy provides different string literals. All kind of strings are actually allowed after the dot:. Text literals are represented in the form of chain of characters called strings. Groovy lets you instantiate java. String objects, as well as GStrings groovy. GString which are also called interpolated strings in other programming languages. Triple-single-quoted strings may span multiple lines. The content of the string can cross line boundaries without the need to split the string in several pieces and without concatenation or newline escape characters:.
If your code is indented, for example in the body of the method of a class, your string will contain the whitespace of the indentation. The Groovy Development Kit contains methods for stripping out the indentation with the String stripIndent method, and with the String stripMargin method that takes a delimiter character to identify the text to remove from the beginning of a string. You will notice that the resulting string contains a newline character as first character.
It is possible to strip that character by escaping the newline with a backslash:. You can escape single quotes with the backslash character to avoid terminating the string literal:. For characters that are not present on your keyboard, you can use unicode escape sequences: a backslash, followed by 'u', then 4 hexadecimal digits.Provides a method to perform custom 'dynamic' type conversion to the given class using the as operator.
Iterate through this String a character at a time collecting either the original character or a transformed replacement String. The transform Closure should return null to indicate that no transformation is required for the given character.
Decodes a hex string to a byte array. The hex string can contain either upper case or lower case letters.
Process each regex group matched substring of the given string. If the closure parameter takes one argument, an array with all match groups is passed to it. If the closure takes as many arguments as there are match groups, then each parameter will be one match group. Process each regex group matched substring of the given pattern. Executes the command specified by self as a command-line process.
For more control over Process construction you can use java. Executes the command specified by self with environment defined by envp and under the working directory dir.
Compare a String representing a number to another. A fluent api style alias for compareTo on BigDecimal. Overloads the left shift operator to provide an easy way to append multiple objects as string representations to a String.
Converts the given string into a Boolean object. If the trimmed string is "true", "y" or "1" ignoring case then the result is true otherwise it is false. Overview Package Class Index. String collectReplacements Closure transform Iterate through this String a character at a time collecting either the original character or a transformed replacement String.
String drop int num A String variant of the equivalent CharSequence method. String eachMatch Pattern pattern, Closure closure Process each regex group matched substring of the given pattern.
Process execute Executes the command specified by self as a command-line process. Process execute String envp, File dir Executes the command specified by self with environment defined by envp and under the working directory dir.
Process execute List envp, File dir Executes the command specified by self with environment defined by envp and under the working directory dir.
StringBuffer leftShift Object value Overloads the left shift operator to provide an easy way to append multiple objects as string representations to a String.
Groovy - Strings
String plus CharSequence value Appends the String representation of the given operand to this string. String take int num A String variant of the equivalent CharSequence method. Character toCharacter Converts the given string into a Character object using the first character in the string.
Methods inherited from class java. Object addShutdownHookanyanyasBooleanasTypeaveragecollectcollectcollectcontainscountdumpeacheachWithIndexequalseveryeveryfindfindfindAllfindAllfindIndexOffindIndexOffindIndexValuesfindIndexValuesfindLastIndexOffindLastIndexOffindResultfindResultflattengetAtgetMetaClassgetMetaPropertyValuesgetPropertiesgrepgrepgroupBygroupByhasPropertyidentityinjectinjectinspectinvokeMethodisisCaseiteratorjoinmetaClassprintprintprintfprintfprintlnprintlnprintlnputAtrespondsTorespondsTosetMetaClasssizesplitsprintfsprintfstreamsumsumtaptoArrayStringtoSpreadMaptoStringuseuseusewithwithwithTraits Methods inherited from interface java.
Comparable numberAwareCompareTo. Methods Detail public Object asType Class c Provides a method to perform custom 'dynamic' type conversion to the given class using the as operator. Parameters: c - the desired class Returns: the converted object Since: 1.
Returns: the decoded bytes as an array Since: 1.Extract a substring by matching a regular expression. Matcher; import java. Regular expression: Split Demo 2. Replacing String Tokenizer 3. String replace 4. String split 5. Simple split 6. Calculating Word Frequencies with Regular Expressions 7. Print all the strings that match a given pattern from a file 8. Quick demo of Regular Expressions substitution 9. Parse an Apache log file with StringTokenizer StringConvenience -- demonstrate java.
String convenience routine Regular Expression Replace Java Regular Expression : Split text Java Regular Expression :split 2 Get all digits from a string Strip extra spaces in a XML string Remove trailing white space from a string Create a string search and replace using regex Split-up string using regular expression Apply proper uppercase and lowercase on a String Regular Expression Search and Replace Program Use Matcher.
Ignore case differences when searching for or replacing substrings.This i am getting the error as invalid xpath expression. Switch To: SmartBear.
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