Package regexp
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func Match ¶
func Match(pattern string, b []byte) (matched bool, err error)
Match reports whether the byte slice b contains any match of the regular expression pattern. More complicated queries need to use Compile and the full Regexp interface.
▸ Example
func MatchReader ¶
func MatchReader(pattern string, r io.RuneReader) (matched bool, err error)
MatchReader reports whether the text returned by the io.RuneReader contains any match of the regular expression pattern. More complicated queries need to use Compile and the full Regexp interface.
func MatchString ¶
func MatchString(pattern string, s string) (matched bool, err error)
MatchString reports whether the string s contains any match of the regular expression pattern. More complicated queries need to use Compile and the full Regexp interface.
▸ Example
func QuoteMeta ¶
func QuoteMeta(s string) string
QuoteMeta returns a string that escapes all regular expression metacharacters inside the argument text; the returned string is a regular expression matching the literal text.
▸ Example
type Regexp ¶
Regexp is the representation of a compiled regular expression. A Regexp is safe for concurrent use by multiple goroutines, except for configuration methods, such as Regexp.Longest.
type Regexp struct {
// contains filtered or unexported fields
}
func Compile ¶
func Compile(expr string) (*Regexp, error)
Compile parses a regular expression and returns, if successful, a Regexp object that can be used to match against text.
When matching against text, the regexp returns a match that begins as early as possible in the input (leftmost), and among those it chooses the one that a backtracking search would have found first. This so-called leftmost-first matching is the same semantics that Perl, Python, and other implementations use, although this package implements it without the expense of backtracking. For POSIX leftmost-longest matching, see CompilePOSIX.
func CompilePOSIX ¶
func CompilePOSIX(expr string) (*Regexp, error)
CompilePOSIX is like Compile but restricts the regular expression to POSIX ERE (egrep) syntax and changes the match semantics to leftmost-longest.
That is, when matching against text, the regexp returns a match that begins as early as possible in the input (leftmost), and among those it chooses a match that is as long as possible. This so-called leftmost-longest matching is the same semantics that early regular expression implementations used and that POSIX specifies.
However, there can be multiple leftmost-longest matches, with different submatch choices, and here this package diverges from POSIX. Among the possible leftmost-longest matches, this package chooses the one that a backtracking search would have found first, while POSIX specifies that the match be chosen to maximize the length of the first subexpression, then the second, and so on from left to right. The POSIX rule is computationally prohibitive and not even well-defined. See https://swtch.com/~rsc/regexp/regexp2.html#posix for details.
func MustCompile ¶
func MustCompile(str string) *Regexp
MustCompile is like Compile but panics if the expression cannot be parsed. It simplifies safe initialization of global variables holding compiled regular expressions.
func MustCompilePOSIX ¶
func MustCompilePOSIX(str string) *Regexp
MustCompilePOSIX is like CompilePOSIX but panics if the expression cannot be parsed. It simplifies safe initialization of global variables holding compiled regular expressions.
func (*Regexp) Copy ¶ 1.6
func (re *Regexp) Copy() *Regexp
Copy returns a new Regexp object copied from re. Calling Regexp.Longest on one copy does not affect another.
Deprecated: In earlier releases, when using a Regexp in multiple goroutines, giving each goroutine its own copy helped to avoid lock contention. As of Go 1.12, using Copy is no longer necessary to avoid lock contention. Copy may still be appropriate if the reason for its use is to make two copies with different Regexp.Longest settings.
func (*Regexp) Expand ¶
func (re *Regexp) Expand(dst []byte, template []byte, src []byte, match []int) []byte
Expand appends template to dst and returns the result; during the append, Expand replaces variables in the template with corresponding matches drawn from src. The match slice should have been returned by Regexp.FindSubmatchIndex.
In the template, a variable is denoted by a substring of the form $name or ${name}, where name is a non-empty sequence of letters, digits, and underscores. A purely numeric name like $1 refers to the submatch with the corresponding index; other names refer to capturing parentheses named with the (?P<name>...) syntax. A reference to an out of range or unmatched index or a name that is not present in the regular expression is replaced with an empty slice.
In the $name form, name is taken to be as long as possible: $1x is equivalent to ${1x}, not ${1}x, and, $10 is equivalent to ${10}, not ${1}0.
To insert a literal $ in the output, use $$ in the template.
▸ Example
func (*Regexp) ExpandString ¶
func (re *Regexp) ExpandString(dst []byte, template string, src string, match []int) []byte
ExpandString is like Regexp.Expand but the template and source are strings. It appends to and returns a byte slice in order to give the calling code control over allocation.
▸ Example
func (*Regexp) Find ¶
func (re *Regexp) Find(b []byte) []byte
Find returns a slice holding the text of the leftmost match in b of the regular expression. A return value of nil indicates no match.
▸ Example
func (*Regexp) FindAll ¶
func (re *Regexp) FindAll(b []byte, n int) [][]byte
FindAll is the 'All' version of Regexp.Find; it returns a slice of all successive matches of the expression, as defined by the 'All' description in the package comment. A return value of nil indicates no match.
▸ Example
func (*Regexp) FindAllIndex ¶
func (re *Regexp) FindAllIndex(b []byte, n int) [][]int
FindAllIndex is the 'All' version of Regexp.FindIndex; it returns a slice of all successive matches of the expression, as defined by the 'All' description in the package comment. A return value of nil indicates no match.
▸ Example
func (*Regexp) FindAllString ¶
func (re *Regexp) FindAllString(s string, n int) []string
FindAllString is the 'All' version of Regexp.FindString; it returns a slice of all successive matches of the expression, as defined by the 'All' description in the package comment. A return value of nil indicates no match.
▸ Example
func (*Regexp) FindAllStringIndex ¶
func (re *Regexp) FindAllStringIndex(s string, n int) [][]int
FindAllStringIndex is the 'All' version of Regexp.FindStringIndex; it returns a slice of all successive matches of the expression, as defined by the 'All' description in the package comment. A return value of nil indicates no match.
func (*Regexp) FindAllStringSubmatch ¶
func (re *Regexp) FindAllStringSubmatch(s string, n int) [][]string
FindAllStringSubmatch is the 'All' version of Regexp.FindStringSubmatch; it returns a slice of all successive matches of the expression, as defined by the 'All' description in the package comment. A return value of nil indicates no match.
▸ Example
func (*Regexp) FindAllStringSubmatchIndex ¶
func (re *Regexp) FindAllStringSubmatchIndex(s string, n int) [][]int
FindAllStringSubmatchIndex is the 'All' version of Regexp.FindStringSubmatchIndex; it returns a slice of all successive matches of the expression, as defined by the 'All' description in the package comment. A return value of nil indicates no match.
▸ Example
func (*Regexp) FindAllSubmatch ¶
func (re *Regexp) FindAllSubmatch(b []byte, n int) [][][]byte
FindAllSubmatch is the 'All' version of Regexp.FindSubmatch; it returns a slice of all successive matches of the expression, as defined by the 'All' description in the package comment. A return value of nil indicates no match.
▸ Example
func (*Regexp) FindAllSubmatchIndex ¶
func (re *Regexp) FindAllSubmatchIndex(b []byte, n int) [][]int
FindAllSubmatchIndex is the 'All' version of Regexp.FindSubmatchIndex; it returns a slice of all successive matches of the expression, as defined by the 'All' description in the package comment. A return value of nil indicates no match.
▸ Example
func (*Regexp) FindIndex ¶
func (re *Regexp) FindIndex(b []byte) (loc []int)
FindIndex returns a two-element slice of integers defining the location of the leftmost match in b of the regular expression. The match itself is at b[loc[0]:loc[1]]. A return value of nil indicates no match.
▸ Example
func (*Regexp) FindReaderIndex ¶
func (re *Regexp) FindReaderIndex(r io.RuneReader) (loc []int)
FindReaderIndex returns a two-element slice of integers defining the location of the leftmost match of the regular expression in text read from the io.RuneReader. The match text was found in the input stream at byte offset loc[0] through loc[1]-1. A return value of nil indicates no match.
func (*Regexp) FindReaderSubmatchIndex ¶
func (re *Regexp) FindReaderSubmatchIndex(r io.RuneReader) []int
FindReaderSubmatchIndex returns a slice holding the index pairs identifying the leftmost match of the regular expression of text read by the io.RuneReader, and the matches, if any, of its subexpressions, as defined by the 'Submatch' and 'Index' descriptions in the package comment. A return value of nil indicates no match.
func (*Regexp) FindString ¶
func (re *Regexp) FindString(s string) string
FindString returns a string holding the text of the leftmost match in s of the regular expression. If there is no match, the return value is an empty string, but it will also be empty if the regular expression successfully matches an empty string. Use Regexp.FindStringIndex or Regexp.FindStringSubmatch if it is necessary to distinguish these cases.
▸ Example
func (*Regexp) FindStringIndex ¶
func (re *Regexp) FindStringIndex(s string) (loc []int)
FindStringIndex returns a two-element slice of integers defining the location of the leftmost match in s of the regular expression. The match itself is at s[loc[0]:loc[1]]. A return value of nil indicates no match.
▸ Example
func (*Regexp) FindStringSubmatch ¶
func (re *Regexp) FindStringSubmatch(s string) []string
FindStringSubmatch returns a slice of strings holding the text of the leftmost match of the regular expression in s and the matches, if any, of its subexpressions, as defined by the 'Submatch' description in the package comment. A return value of nil indicates no match.
▸ Example
func (*Regexp) FindStringSubmatchIndex ¶
func (re *Regexp) FindStringSubmatchIndex(s string) []int
FindStringSubmatchIndex returns a slice holding the index pairs identifying the leftmost match of the regular expression in s and the matches, if any, of its subexpressions, as defined by the 'Submatch' and 'Index' descriptions in the package comment. A return value of nil indicates no match.
func (*Regexp) FindSubmatch ¶
func (re *Regexp) FindSubmatch(b []byte) [][]byte
FindSubmatch returns a slice of slices holding the text of the leftmost match of the regular expression in b and the matches, if any, of its subexpressions, as defined by the 'Submatch' descriptions in the package comment. A return value of nil indicates no match.
▸ Example
func (*Regexp) FindSubmatchIndex ¶
func (re *Regexp) FindSubmatchIndex(b []byte) []int
FindSubmatchIndex returns a slice holding the index pairs identifying the leftmost match of the regular expression in b and the matches, if any, of its subexpressions, as defined by the 'Submatch' and 'Index' descriptions in the package comment. A return value of nil indicates no match.
▸ Example
func (*Regexp) LiteralPrefix ¶
func (re *Regexp) LiteralPrefix() (prefix string, complete bool)
LiteralPrefix returns a literal string that must begin any match of the regular expression re. It returns the boolean true if the literal string comprises the entire regular expression.
func (*Regexp) Longest ¶ 1.1
func (re *Regexp) Longest()
Longest makes future searches prefer the leftmost-longest match. That is, when matching against text, the regexp returns a match that begins as early as possible in the input (leftmost), and among those it chooses a match that is as long as possible. This method modifies the Regexp and may not be called concurrently with any other methods.
▸ Example
func (*Regexp) MarshalText ¶ 1.21
func (re *Regexp) MarshalText() ([]byte, error)
MarshalText implements encoding.TextMarshaler. The output matches that of calling the Regexp.String method.
Note that the output is lossy in some cases: This method does not indicate POSIX regular expressions (i.e. those compiled by calling CompilePOSIX), or those for which the Regexp.Longest method has been called.
func (*Regexp) Match ¶
func (re *Regexp) Match(b []byte) bool
Match reports whether the byte slice b contains any match of the regular expression re.
▸ Example
func (*Regexp) MatchReader ¶
func (re *Regexp) MatchReader(r io.RuneReader) bool
MatchReader reports whether the text returned by the io.RuneReader contains any match of the regular expression re.
func (*Regexp) MatchString ¶
func (re *Regexp) MatchString(s string) bool
MatchString reports whether the string s contains any match of the regular expression re.
▸ Example
func (*Regexp) NumSubexp ¶
func (re *Regexp) NumSubexp() int
NumSubexp returns the number of parenthesized subexpressions in this Regexp.
▸ Example
func (*Regexp) ReplaceAll ¶
func (re *Regexp) ReplaceAll(src, repl []byte) []byte
ReplaceAll returns a copy of src, replacing matches of the Regexp with the replacement text repl. Inside repl, $ signs are interpreted as in Regexp.Expand.
▸ Example
func (*Regexp) ReplaceAllFunc ¶
func (re *Regexp) ReplaceAllFunc(src []byte, repl func([]byte) []byte) []byte
ReplaceAllFunc returns a copy of src in which all matches of the Regexp have been replaced by the return value of function repl applied to the matched byte slice. The replacement returned by repl is substituted directly, without using Regexp.Expand.
func (*Regexp) ReplaceAllLiteral ¶
func (re *Regexp) ReplaceAllLiteral(src, repl []byte) []byte
ReplaceAllLiteral returns a copy of src, replacing matches of the Regexp with the replacement bytes repl. The replacement repl is substituted directly, without using Regexp.Expand.
func (*Regexp) ReplaceAllLiteralString ¶
func (re *Regexp) ReplaceAllLiteralString(src, repl string) string
ReplaceAllLiteralString returns a copy of src, replacing matches of the Regexp with the replacement string repl. The replacement repl is substituted directly, without using Regexp.Expand.
▸ Example
func (*Regexp) ReplaceAllString ¶
func (re *Regexp) ReplaceAllString(src, repl string) string
ReplaceAllString returns a copy of src, replacing matches of the Regexp with the replacement string repl. Inside repl, $ signs are interpreted as in Regexp.Expand.
▸ Example
func (*Regexp) ReplaceAllStringFunc ¶
func (re *Regexp) ReplaceAllStringFunc(src string, repl func(string) string) string
ReplaceAllStringFunc returns a copy of src in which all matches of the Regexp have been replaced by the return value of function repl applied to the matched substring. The replacement returned by repl is substituted directly, without using Regexp.Expand.
▸ Example
func (*Regexp) Split ¶ 1.1
func (re *Regexp) Split(s string, n int) []string
Split slices s into substrings separated by the expression and returns a slice of the substrings between those expression matches.
The slice returned by this method consists of all the substrings of s not contained in the slice returned by Regexp.FindAllString. When called on an expression that contains no metacharacters, it is equivalent to strings.SplitN.
Example:
s := regexp.MustCompile("a*").Split("abaabaccadaaae", 5)
// s: ["", "b", "b", "c", "cadaaae"]
The count determines the number of substrings to return:
- n > 0: at most n substrings; the last substring will be the unsplit remainder;
- n == 0: the result is nil (zero substrings);
- n < 0: all substrings.
▸ Example
func (*Regexp) String ¶
func (re *Regexp) String() string
String returns the source text used to compile the regular expression.
func (*Regexp) SubexpIndex ¶ 1.15
func (re *Regexp) SubexpIndex(name string) int
SubexpIndex returns the index of the first subexpression with the given name, or -1 if there is no subexpression with that name.
Note that multiple subexpressions can be written using the same name, as in (?P<bob>a+)(?P<bob>b+), which declares two subexpressions named "bob". In this case, SubexpIndex returns the index of the leftmost such subexpression in the regular expression.
▸ Example
func (*Regexp) SubexpNames ¶
func (re *Regexp) SubexpNames() []string
SubexpNames returns the names of the parenthesized subexpressions in this Regexp. The name for the first sub-expression is names[1], so that if m is a match slice, the name for m[i] is SubexpNames()[i]. Since the Regexp as a whole cannot be named, names[0] is always the empty string. The slice should not be modified.
▸ Example
func (*Regexp) UnmarshalText ¶ 1.21
func (re *Regexp) UnmarshalText(text []byte) error
UnmarshalText implements encoding.TextUnmarshaler by calling Compile on the encoded value.