Regular Expressions 101

Save & Manage Regex

  • Current Version: 7
  • Save & Share
  • Community Library

Flavor

  • PCRE2 (PHP)
  • ECMAScript (JavaScript)
  • Python
  • Golang
  • Java
  • .NET 7.0 (C#)
  • Rust
  • PCRE (Legacy)
  • Regex Flavor Guide

Function

  • Match
  • Substitution
  • List
  • Unit Tests
Sponsors
There are currently no sponsors. Become a sponsor today!
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"(?:(?# Pattern before filename\n" r" )(?:\[download\] )?Destination: (?#\n" r")|(?#\n" r" )\[download\] (?#\n" r")|(?#\n" r" )Adding metadata to \"(?#\n" r"))(?#\n" r")((?# CAPTURE GROUP: filename pattern\n" r" )\/?[^\/\\\n]+(?:\/|\\)(?# Capture first folder\n" r" )(?:(?#\n" r" )[^\n\.]*(?# Stop capturing if point, to check\n" r" )(?!\.f\d{1,4}\.(?:webm|mov|mp4))(?# Checking this is not a partial download\n" r" )\.(?# Can now capture the point\n" r" ))+(?#\n" r" )(?:webm|mov|mp4)(?#\n" r"))(?#\n" r")\n?"), flags=re.MULTILINE) test_str = ("=============================\n" " GOOD TESTS\n" "=============================\n" "[download] /root/.local/share/ICONO_TESTS/1678445152615210072_0.33914607510068406/yt-videos/BURGER KLEAN - 1080.mp4 has already been downloaded\n" "[download] /root/.local/share/ICONO_TESTS/small/yt-videos/hello.mp4 has already been downloaded\n" "[download] /root/local/share/ICONO_TESTS/small/yt-videos/hello.mp4 has already been downloaded\n" "Destination: /root/.local/share/ICONO_TESTS/1678445152615210072_0.33914607510068406/yt-videos/Hi Anxiety： Lana Condor - 1080.mp4\n" "[download] Destination: /root/.local/share/ICONO_TESTS/1678445152615210072_0.33914607510068406/yt-videos/#histoire #vrai #fyp #foryou #pourtoi #fyp - NA.mp4\n" "Destination: C:/Users/Adrien/AppData/Local/ICONO/ICONO_TESTS/yt-videos/ICONO in a minute or so. - 1080.webm\n" "Destination: C:/Users/Adrien/AppData/Local/ICONO/ICONO_TESTS/yt-videos/ICONO in a minute or so - 1080.webm\n" "Destination: C:/Users/Adrien/AppData/Local/ICONO/ICONO_TESTS/yt-videos/ICONO.webm\n" "Destination: C:/Users/Adrien/AppData/Local/ICONO/ICONO_TESTS/yt-videos/ICONO_123.webm\n" "Destination: C:/Users/Adrien/AppData/Local/ICONO/ICONO_TESTS/yt-videos/ICONO_1.2.3.mp4\n" "xxx Destination: C:/Users/Adrien/AppData/Local/ICONO/ICONO_TESTS/yt-videos/ICONO in a minute or so - 1080.mov\n" "xxx Adding metadata to \"C:/Users/Adrien/AppData/Local/ICONO/ICONO_TESTS/yt-videos/ICONO in a minute or so - 1080.mov\"\n" "[Metadata] Adding metadata to \"C:/Users/Adrien/AppData/Local/ICONO/ICONO_TESTS/yt-videos/ICONO in a minute or so - 1080.mov\"\n" "[Metadata] Adding metadata to \"C:/Users/Adrien/AppData/Local/ICONO/ICONO_TESTS/yt-videos/ICONO in a minute or so - 1080.mov\"\n" "[Metadata] Adding metadata to \"/home/ezalos/.local/share/ICONO_TESTS/yt-videos/ICONO in a minute or so. - 1080.mov\"\n" "[Metadata] Adding metadata to \"/home/ezalos/.local/share/ICONO_TESTS/yt-videos/ICONO in a minute or so. - 1080.mov\"\n\n" "Adding metadata to \"C:\\Users\\Adrien\\AppData\\Local\\ICONO\\ICONO_TESTS\\1678715744635004900_0.6505223019081934\\yt-videos\\BURGER KLEAN - 1080.mp4\n\n" "=============================\n" " BAD TESTS\n" "=============================\n" " def test_download(browser: Chrome):\n" " app_actions = AppActions(browser, test_name=\"test_download\")\n" " app_actions.screenshot()\n" " for url in url_to_test:\n" " file_path = app_actions.download_video(url)\n" "> assert os.path.isfile(file_path)\n" "E AssertionError: assert False\n" "E + where False = <function isfile at 0x000002D095AFF160>('C:/Users/Adrien/AppData/Local/ICONO/ICONO_TESTS/yt-videos/ICONO in a minute or so. - 1080.f248.webm')\n" "E + where <function isfile at 0x000002D095AFF160> = <module 'ntpath' from 'C:\\\\Users\\\\Adrien\\\\mambaforge\\\\envs\\\\ICONO-prod\\\\lib\\\\ntpath.py'>.isfile\n" "E + where <module 'ntpath' from 'C:\\\\Users\\\\Adrien\\\\mambaforge\\\\envs\\\\ICONO-prod\\\\lib\\\\ntpath.py'> = os.path\n" "Destination: C:/Users/Adrien/AppData/Local/ICONO/ICONO_TESTS/yt-videos/ICONO in a minute or so - 1080.f248.webm\n" "Destination: C:/Users/Adrien/AppData/Local/ICONO/ICONO_TESTS/yt-videos/ICONO in a minute or so - 1080.f248.mov\n" "DEBUG : 35954 ms [Thread 140114533140224] src.back.download.ytdlp.execute_command:25 || STDOUT: [download] 0.1% of ~ 966.70KiB at 43.60KiB/s ETA 00:22 (frag 0/1)\n" "DEBUG : 35954 ms [Thread 140114533140224] src.back.download.ytdlp.execute_command:25 || STDOUT: [download] 0.3% of ~ 966.70KiB at 127.60KiB/s ETA 00:07 (frag 0/1)\n" "DEBUG : 35954 ms [Thread 140114533140224] src.back.download.ytdlp.execute_command:25 || STDOUT: [download] 0.7% of ~ 966.70KiB at 291.21KiB/s ETA 00:03 (frag 0/1)\n" "DEBUG : 35954 ms [Thread 140114533140224] src.back.download.ytdlp.execute_command:25 || STDOUT: [download] 1.6% of ~ 966.70KiB at 610.67KiB/s ETA 00:01 (frag 0/1)\n" "DEBUG : 35954 ms [Thread 140114533140224] src.back.download.ytdlp.execute_command:25 || STDOUT: [download] 3.2% of ~ 966.70KiB at 1.21MiB/s ETA 00:00 (frag 0/1)\n" "DEBUG : 35954 ms [Thread 140114533140224] src.back.download.ytdlp.execute_command:25 || STDOUT: [download] 6.5% of ~ 966.70KiB at 2.30MiB/s ETA 00:00 (frag 0/1)\n" "DEBUG : 35954 ms [Thread 140114533140224] src.back.download.ytdlp.execute_command:25 || STDOUT: [download] 13.1% of ~ 966.70KiB at 4.33MiB/s ETA 00:00 (frag 0/1)\n" "DEBUG : 35954 ms [Thread 140114533140224] src.back.download.ytdlp.execute_command:25 || STDOUT: [download] 26.4% of ~ 966.70KiB at 8.06MiB/s ETA 00:00 (frag 0/1)\n" "DEBUG : 35954 ms [Thread 140114533140224] src.back.download.ytdlp.execute_command:25 || STDOUT: [download] 52.9% of ~ 966.70KiB at 14.72MiB/s ETA 00:00 (frag 0/1)\n" "DEBUG : 35955 ms [Thread 140114533140224] src.back.download.ytdlp.execute_command:25 || STDOUT: [download] 100.0% of ~ 966.70KiB at 25.08MiB/s ETA 00:00 (frag 0/1)\n" "DEBUG : 35955 ms [Thread 140114533140224] src.back.download.ytdlp.execute_command:25 || STDOUT: [download] 100.0% of ~ 966.70KiB at 24.67MiB/s ETA 00:00 (frag 1/1)\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