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

/
/
g

Test String

Code Generator

Language

Generated Code

# coding=utf8 # the above tag defines encoding for this document and is for Python 2.x compatibility import re regex = r"interface\s([\S]+?)\.(\d+)\s+(description\s(?:[^a-zA-Z0-9]?([\S]+)[^a-zA-Z0-9]?))*(?:encapsulation\sdot1q\s(\d+)\s*)*(?:second-dot1q\s(\S+)\s+)*(?:rewrite\singress\stag\s(.+?)\s{2,})*(?:service-policy\sinput\s([\S]+)\s+)*(?:service-policy\soutput\s([\S]+))*.+?(?:\s*!|\s+service\sinstance)" test_str = ("interface Loopback9 description RIFERIMENTO LDP/EoMPLS ip address 172.16.116.23 255.255.255.255!\n" "interface Port-channel2 description KdC-TEST_ESPOSITO/CANDIDO_3263 mtu 9206 no ip address logging event link-status load-interval 30 shutdown\n" " service instance 301 ethernet description LINK-to-OLO encapsulation dot1q 269 second-dot1q 301 rewrite ingress tag pop 1 symmetric group 12333 service-policy input BTS_P01_B-96k_B3-0_B5-0_B6-0_IN service-policy output BTS_P01_B-96k_B3-0_B5-0_B6-0_OUT xconnect 172.16.116.249 570435069 encapsulation mpls mtu 9206 \n" " service instance 301 ethernet description LINK-to-OLO encapsulation dot1q 269 second-dot1q 301 rewrite ingress tag pop 1 symmetric group 12333 service-policy input BTS_P01_B-96k_B3-0_B5-0_B6-0_IN service-policy output BTS_P01_B-96k_B3-0_B5-0_B6-0_OUT xconnect 172.16.116.249 570435069 encapsulation mpls mtu 9206 !\n" " service instance 4001 ethernet description SI_VLAN-PING encapsulation dot1q 4001 rewrite ingress tag pop 1 symmetric service-policy input PING_LIMIT bridge-domain 4001 !!\n" "interface Port-channel2.302 description \"vlan_pseudo_lato_olo\" encapsulation dot1q 1327 second-dot1q 1001 rewrite ingress tag pop 1 symmetric service-policy input GBE_remark_in service-policy output GBE_remark_out !\n\n" "interface Port-channel2.302 description test_subif!") matches = re.finditer(regex, test_str) for matchNum, match in enumerate(matches, start=1): print ("Match {matchNum} was found at {start}-{end}: {match}".format(matchNum = matchNum, start = match.start(), end = match.end(), match = match.group())) for groupNum in range(0, len(match.groups())): groupNum = groupNum + 1 print ("Group {groupNum} found at {start}-{end}: {group}".format(groupNum = groupNum, start = match.start(groupNum), end = match.end(groupNum), group = match.group(groupNum))) # Note: for Python 2.7 compatibility, use ur"" to prefix the regex and u"" to prefix the test string and substitution.

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 Python, please visit: https://docs.python.org/3/library/re.html