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

r"
"
gm

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"^UVM_[A-Z]*|build.+?(?=\()|[0-9]+(?=\))|(?<=@ )[0-9]+|(?<= \[).*?(?=\]\s)|(?<=: ).*?(?= \[)|((?<=\]).*())" test_str = ("UVM_INFO build/vcs-rtl-default-queue/sbu_tb/sv/SbuSbMonitor/bmiTransRecorder.sv(495) @ 4725749: reporter@@BMI_TXN [BMI_RECORDER] @ 4725749 [BMI ID: 95] bmiDone=0 nbuId=0xa biuId=0x0 devRst=0 m_error=0 type=write_data snpId=0x5 txnId=0x1c124 devTag=0x0 wrIdx=0x0 addr=0x300ac len=0x4 space=3 dev_cmd=unknown data=0x25c20d74288413f2387891d50000000000000119ec331542f7518539c4101a2d7a0ccdbfd7837f2f918651f3dda1de0c54fb652228b2c1ced2ae6bd16dd302dd lv=0x0\n" "UVM_INFO build/vcs-test_bmi_rsp-default-queue/sbu_tb/sv/SmmuModel/tlb_cache.sv(130) @ 264291: tlb_cache_h [tlb_cache] TLB_CACHE:: BEFORE pagesize[ 310][ 0] = 0 AFTER - pagesize[ 310][ 0] = 1\n") matches = re.finditer(regex, test_str, re.MULTILINE) 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