Return all matches of this regexp in given character sequence as a scala.util.matching.Regex.MatchIterator, which is a special scala.collection.Iterator that returns the matched strings, but can also be converted into a normal iterator that returns objects of type scala.util.matching.Regex.Match that can be queried for data such as the text that precedes the match, subgroups, etc.
Return all matches of this regexp in given character sequence as a scala.util.matching.Regex.MatchIterator, which is a special scala.collection.Iterator that returns the matched strings, but can also be converted into a normal iterator that returns objects of type scala.util.matching.Regex.Match that can be queried for data such as the text that precedes the match, subgroups, etc.
The text to match against.
A scala.util.matching.Regex.MatchIterator of all matches.
for (words <- """\w+""".r findAllIn "A simple example.") yield words
Return all matches of this regexp in given character sequence as a scala.collection.Iterator of scala.util.matching.Regex.Match.
Return all matches of this regexp in given character sequence as a scala.collection.Iterator of scala.util.matching.Regex.Match.
The text to match against.
A scala.collection.Iterator of scala.util.matching.Regex.Match for all matches.
for (words <- """\w+""".r findAllMatchIn "A simple example.") yield words.start
Return optionally first matching string of this regexp in given character sequence, or None if it does not exist.
Return optionally first matching string of this regexp in given character sequence, or None if it does not exist.
The text to match against.
An scala.Option of the first matching string in the text.
"""\w+""".r findFirstIn "A simple example." foreach println // prints "A"
Return optionally first match of this regexp in given character sequence, or None if it does not exist.
Return optionally first match of this regexp in given character sequence, or None if it does not exist.
The main difference between this method and findFirstIn is that the (optional) return
type for this is scala.util.matching.Regex.Match, through which more
data can be obtained about the match, such as the strings that precede and follow it,
or subgroups.
The text to match against.
A scala.Option of scala.util.matching.Regex.Match of the first matching string in the text.
("""[a-z]""".r findFirstMatchIn "A simple example.") map (_.start) // returns Some(2), the index of the first match in the text
Return optionally match of this regexp at the beginning of the given character sequence, or None if regexp matches no prefix of the character sequence.
Return optionally match of this regexp at the beginning of the given character sequence, or None if regexp matches no prefix of the character sequence.
The main difference from this method to findFirstMatchIn is that
this method will not return any matches that do not begin at the
start of the text being matched against.
The text to match against.
A scala.Option of the scala.util.matching.Regex.Match of the matched string.
"""\w+""".r findPrefixMatchOf "A simple example." map (_.after) // returns Some(" simple example.")
Return optionally match of this regexp at the beginning of the given character sequence, or None if regexp matches no prefix of the character sequence.
Return optionally match of this regexp at the beginning of the given character sequence, or None if regexp matches no prefix of the character sequence.
The main difference from this method to findFirstIn is that this
method will not return any matches that do not begin at the start
of the text being matched against.
The text to match against.
A scala.Option of the matched prefix.
"""[a-z]""".r findPrefixOf "A simple example." // returns None, since the text does not begin with a lowercase letter
Returns string formatted according to given format string.
Returns string formatted according to given format string.
Format strings are as for String.format
(@see java.lang.String.format).
The compiled pattern
Replaces all matches using a replacer function.
Replaces all matches using a replacer function. The replacer function takes a scala.util.matching.Regex.Match so that extra information can be obtained from the match. For example:
import scala.util.matching.Regex val datePattern = new Regex("""(\d\d\d\d)-(\d\d)-(\d\d)""", "year", "month", "day") val text = "From 2011-07-15 to 2011-07-17" val repl = datePattern replaceAllIn (text, m => m.group("month")+"/"+m.group("day"))
In the replacement String, a dollar sign ($) followed by a number will be
interpreted as a reference to a group in the matched pattern, with numbers
1 through 9 corresponding to the first nine groups, and 0 standing for the
whole match. Any other character is an error. The backslash (\) character
will be interpreted as an escape character, and can be used to escape the
dollar sign. One can use scala.util.matching.Regex's quoteReplacement
to automatically escape these characters.
The string to match.
The function which maps a match to another string.
The target string after replacements.
Replaces all matches by a string.
Replaces all matches by a string.
In the replacement String, a dollar sign ($) followed by a number will be
interpreted as a reference to a group in the matched pattern, with numbers
1 through 9 corresponding to the first nine groups, and 0 standing for the
whole match. Any other character is an error. The backslash (\) character
will be interpreted as an escape character, and can be used to escape the
dollar sign. One can use scala.util.matching.Regex's quoteReplacement
to automatically escape these characters.
The string to match
The string that will replace each match
The resulting string
"""\d+""".r replaceAllIn ("July 15", "" ) // returns "July"
Replaces the first match by a string.
Replaces the first match by a string.
In the replacement String, a dollar sign ($) followed by a number will be
interpreted as a reference to a group in the matched pattern, with numbers
1 through 9 corresponding to the first nine groups, and 0 standing for the
whole match. Any other character is an error. The backslash (\) character
will be interpreted as an escape character, and can be used to escape the
dollar sign. One can use scala.util.matching.Regex's quoteReplacement
to automatically escape these characters.
The string to match
The string that will replace the match
The resulting string
Replaces some of the matches using a replacer function that returns an scala.Option.
Replaces some of the matches using a replacer function that returns an scala.Option. The replacer function takes a scala.util.matching.Regex.Match so that extra information can be btained from the match. For example:
import scala.util.matching.Regex._ val map = Map("x" -> "a var", "y" -> """some $ and \ signs""") val text = "A text with variables %x, %y and %z." val varPattern = """%(\w+)""".r val mapper = (m: Match) => map get (m group 1) map (quoteReplacement(_)) val repl = varPattern replaceSomeIn (text, mapper)
In the replacement String, a dollar sign ($) followed by a number will be
interpreted as a reference to a group in the matched pattern, with numbers
1 through 9 corresponding to the first nine groups, and 0 standing for the
whole match. Any other character is an error. The backslash (\) character
will be interpreted as an escape character, and can be used to escape the
dollar sign. One can use scala.util.matching.Regex's quoteReplacement
to automatically escape these characters.
The string to match.
The function which optionally maps a match to another string.
The target string after replacements.
Splits the provided character sequence around matches of this regexp.
Splits the provided character sequence around matches of this regexp.
The character sequence to split
The array of strings computed by splitting the input around matches of this regexp
The string defining the regular expression
The string defining the regular expression
Create a new Regex with the same pattern, but no requirement that the entire String matches in extractor patterns.
Create a new Regex with the same pattern, but no requirement that the entire String matches in extractor patterns. For instance, the strings shown below lead to successful matches, where they would not otherwise.
val dateP1 = """(\d\d\d\d)-(\d\d)-(\d\d)""".r.unanchored val dateP1(year, month, day) = "Date 2011-07-15" val copyright: String = "Date of this document: 2011-07-15" match { case dateP1(year, month, day) => "Copyright "+year case _ => "No copyright" }
The new unanchored regex
Tries to match on a scala.util.matching.Regex.Match.
Tries to match on a scala.util.matching.Regex.Match. A previously failed match results in None. If a successful match was made against the current pattern, then that result is used. Otherwise, this Regex is applied to the previously matched input, and the result of that match is used.
Tries to match the String representation of a scala.Char.
Tries to match the String representation of a scala.Char. If the match succeeds, the result is the first matching group if any groups are defined, or an empty Sequence otherwise.
For example:
val cat = "cat" // the case must consume the group to match val r = """(\p{Lower})""".r cat(0) match { case r(x) => true } cat(0) match { case r(_) => true } cat(0) match { case r(_*) => true } cat(0) match { case r() => true } // no match // there is no group to extract val r = """\p{Lower}""".r cat(0) match { case r(x) => true } // no match cat(0) match { case r(_) => true } // no match cat(0) match { case r(_*) => true } // matches cat(0) match { case r() => true } // matches // even if there are multiple groups, only one is returned val r = """((.))""".r cat(0) match { case r(_) => true } // matches cat(0) match { case r(_,_) => true } // no match
The Char to match
The match
Tries to match a java.lang.CharSequence.
Tries to match a java.lang.CharSequence.
If the match succeeds, the result is a list of the matching
groups (or a null element if a group did not match any input).
If the pattern specifies no groups, then the result will be an empty list
on a successful match.
This method attempts to match the entire input by default; to find the next matching subsequence, use an unanchored Regex.
For example:
val p1 = "ab*c".r val p1Matches = "abbbc" match { case p1() => true case _ => false } val p2 = "a(b*)c".r val numberOfB = "abbbc" match { case p2(b) => Some(b.length) case _ => None } val p3 = "b*".r.unanchored val p3Matches = "abbbc" match { case p3() => true case _ => false }
The string to match
The matches
Tries to match target.
Tries to match target.
The string to match
The matches
(Since version 2.11.0) Extracting a match result from anything but a CharSequence or Match is deprecated
This class provides methods for creating and using regular expressions. It is based on the regular expressions of the JDK since 1.4.
Its main goal is to extract strings that match a pattern, or the subgroups that make it up. For that reason, it is usually used with for comprehensions and matching (see methods for examples).
A Regex is created from a java.lang.String representation of the regular expression pattern1. That pattern is compiled during construction, so frequently used patterns should be declared outside loops if performance is of concern. Possibly, they might be declared on a companion object, so that they need only to be initialized once.
The canonical way of creating regex patterns is by using the method
r, provided on java.lang.String through an implicit conversion into scala.collection.immutable.WrappedString. Using triple quotes to write these strings avoids having to quote the backslash character (\).Using the constructor directly, on the other hand, makes it possible to declare names for subgroups in the pattern.
For example, both declarations below generate the same regex, but the second one associate names with the subgroups.
There are two ways of using a
Regexto find a pattern: calling methods on Regex, such asfindFirstInorfindAllIn, or using it as an extractor in a pattern match.Note, however, that when Regex is used as an extractor in a pattern match, it only succeeds if the whole text can be matched. For this reason, one usually calls a method to find the matching substrings, and then use it as an extractor to break match into subgroups.
As an example, the above patterns can be used like this:
Regex does not provide a method that returns a scala.Boolean. One can use java.lang.String
matchesmethod, or, ifRegexis preferred, either ignore the return value or test theOptionfor emptyness. For example:There are also methods that can be used to replace the patterns on a text. The substitutions can be simple replacements, or more complex functions. For example:
You can use special pattern syntax constructs like
(?idmsux-idmsux)¹ to switch various regex compilation options likeCASE_INSENSITIVEorUNICODE_CASE.1.1, 29/01/2008
¹ A detailed description is available in java.util.regex.Pattern.
java.util.regex.Pattern