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"
"

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"([\.\w\?]+)\s+([\dABCDEF]+) - ([\dABCDEF]+)\s+([\dABCDEF]+)" test_str = (".noinit 00001000 - 00001012 13 DATA (1 bytes space 00001013 - 00001013)\n" ".ramcode 00001014 - 000017CB 7B8 DATA \n" ".bss 000017CC - 00002A6A 129F DATA (1 bytes space 00002A6B - 00002A6B)\n" ".data 00002A6C - 00002B35 CA DATA \n" "WARNING: Non-dotted segment name DSPSEGMENT2.DRIVER120\n" "DSPSEGMENT2.DRIVER120 00002B36 - 00002B3D 8 DATA \n" ".ISOBUFFERS 00002B3E - 00002CBD 180 DATA \n" ".uart 00002CBE - 00002DBD 100 DATA (562 bytes space 00002DBE - 00002FEF)\n" ".qspidata 00002FF0 - 00002FFF 10 DATA \n" ".icache 00003000 - 00003FFF 1000 DATA (20480 bytes space 00004000 - 00008FFF)\n" ".rsstack0 00009000 - 000092FF 300 DATA \n" ".rsmails0 00009300 - 000096FF 400 DATA \n" ".trace 00009700 - 000098FF 200 DATA ") matches = re.search(regex, test_str) if matches: print ("Match was found at {start}-{end}: {match}".format(start = matches.start(), end = matches.end(), match = matches.group())) for groupNum in range(0, len(matches.groups())): groupNum = groupNum + 1 print ("Group {groupNum} found at {start}-{end}: {group}".format(groupNum = groupNum, start = matches.start(groupNum), end = matches.end(groupNum), group = matches.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