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
Processing...

Test String

Code Generator

Language

Generated Code

import re regex = re.compile(r"^(?<parameter>[^:]+)\:\s*(?:(?<value>[A-Za-z]+\:\s*[^>]+))\s*(?<description>.*)", flags=re.MULTILINE) test_str = ("pts_time: PTS: 1741047514> Time: 19345 sec > (hh:mm:ss.ms) 05:22:24.972\n" "pts_time: PTS: 1741047514 [0x67C646DA] > Time: 19345 sec > (hh:mm:ss.ms) 05:22:24.972\n" "private_indicator: '0' reserved: '11'\n" "section_length: 0x39 (57) protocol_version: 0\n" "encrypted_packet: 0 no part of this message is encrypted\n" "encryption_algorithm: 0 No encryption\n" "pts_adjustment: 0xFFFF7F18 (33000) > Time: 95443.4 sec > (hh:mm:ss.ms) 26:30:43.351\n" "cw_index: 0x00 (0) tier: 0x0FFF (4095)\n" "splice_command_length: 0x0005 (5) splice_command_type: 0x06 (6) time_signal [] time_signal: > Time: 19345 sec > (hh:mm:ss.ms) 05:22:24.972\n" "time_specified_flag: 1 presence of the pts_time field\n" "reserved: 0x3F (63) descriptor_loop_length: 35 [] Descriptors: [] segmentation_descriptor (0x02): Content Identification (0x01)\n" "descriptor_tag: 0x02 (2) descriptor_length: 0x21 (33)\n" "identifier: 0x43554549 (CUEI) segmentation_event_id: 0x00000001 (1)\n" "segmentation_event_cancel_indicator: '0' a previously sent segmentation event, identified by segmentation_event_id, has NOT been cancelled\n" "reserved: 0x7F (127) program_segmentation_flag: '1' the message refers to a Program Segmentation Point and that the mode is the Program Segmentation Mode whereby all PIDs/components of the program are to be segmented\n" "segmentation_duration_flag: '0' No presence of segmentation_duration field\n" "delivery_not_restricted_flag: '1' the next five bits are reserved\n" "reserved: 0x1F (31) segmentation_upid_type: 0x01 (1) Deprecated: use type 0x0C; The segmentation_upid does not follow a standard naming scheme.\n" "segmentation_upid_length: 0x12 (18) segmentation_type_id: 0x01 (1) Content Identification\n" "segment_num: 0x01 (1) segments_expected: 0x01 (1)\n" "CRC_32: 0x46D15AF3 CRC OK\n\n" "// try this one first\n" "// (a) ^(?<parameter>[^:]+)\\:\\s*(?:(?<value>[A-Za-z]+\\:\\s*[^>]+))\n" "// (b) ^(?<parameter>[^:]+)\\:\\s*(?:(?<value>[A-Za-z]+\\:\\s*[^>]+))\\s*(?<description>.*)\n\n" "// in case of no match of the above one use the second\n" "// (a) ^(?<parameter>[^:]+):\\s*(?<value>[\\w']+(?:\\s*\\([^)]*\\))*)\n" "// (b) ^(?<parameter>[^:]+):\\s*(?<value>[\\w']+(?:\\s*\\([^)]*\\))*)\\s*(?<description>.*)\n\n" "// substitution:\n" "// [\"$1\", \"$2\", \"$3\"]\n") matches = regex.finditer(test_str) for match_num, match in enumerate(matches, start=1): print(f"Match {match_num} was found at {match.start()}-{match.end()}: {match.group()}") for group_num, group in enumerate(match.groups(), start=1): print(f"Group {group_num} found at {match.start(group_num)}-{match.end(group_num)}: {group}")

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