Regular Expressions 101

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An explanation of your regex will be automatically generated as you type.
Detailed match information will be displayed here automatically.
  • All Tokens
  • Common Tokens
  • General Tokens
  • Anchors
  • Meta Sequences
  • Quantifiers
  • Group Constructs
  • Character Classes
  • Flags/Modifiers
  • Substitution
  • A single character of: a, b or c
    [abc]
  • A character except: a, b or c
    [^abc]
  • A character in the range: a-z
    [a-z]
  • A character not in the range: a-z
    [^a-z]
  • A character in the range: a-z or A-Z
    [a-zA-Z]
  • Any single character
    .
  • Alternate - match either a or b
    a|b
  • Any whitespace character
    \s
  • Any non-whitespace character
    \S
  • Any digit
    \d
  • Any non-digit
    \D
  • Any word character
    \w
  • Any non-word character
    \W
  • Non-capturing group
    (?:...)
  • Capturing group
    (...)
  • Zero or one of a
    a?
  • Zero or more of a
    a*
  • One or more of a
    a+
  • Exactly 3 of a
    a{3}
  • 3 or more of a
    a{3,}
  • Between 3 and 6 of a
    a{3,6}
  • Start of string
    ^
  • End of string
    $
  • A word boundary
    \b
  • Non-word boundary
    \B

Regular Expression
No Match

/
/
gm

Test String

Code Generator

Language

Generated Code

package main import ( "regexp" "fmt" ) func main() { var re = regexp.MustCompile(`(?m)^(.*?) : (.+? MB\/s)( \[.*)?$`) var str = `Sequential Read : 135.091 MB/s Sequential Write : 126.046 MB/s Random Read 512KB : 44.569 MB/s Random Write 512KB : 117.965 MB/s Random Read 4KB (QD=1) : 0.468 MB/s [ 114.4 IOPS] Random Write 4KB (QD=1) : 8.412 MB/s [ 2053.6 IOPS] Random Read 4KB (QD=32) : 0.654 MB/s [ 159.6 IOPS] Random Write 4KB (QD=32) : 10.751 MB/s [ 2624.7 IOPS] Test : 1000 MB [C: 7.3% (64.9/889.4 GB)] (x5) Date : 2015/12/09 22:06:02 OS : Windows 8.1 [6.3 Build 9600] (x64)` for i, match := range re.FindAllString(str, -1) { fmt.Println(match, "found at index", i) } }

Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for Golang, please visit: https://golang.org/pkg/regexp/