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

const regex = new RegExp('(?:(?# Pattern before filename )(?:\\[download\\] )?Destination: (?# )|(?# )\\[download\\] (?# )|(?# )Adding metadata to \\"(?# ))(?# )((?# CAPTURE GROUP: filename pattern )\\/?[^\\/\\\\\\n]+(?:\\/|\\\\)(?# Capture first folder )(?:(?# )[^\\n\\.]*(?# Stop capturing if point, to check )(?!\\.f\\d{1,4}\\.(?:webm|mov|mp4))(?# Checking this is not a partial download )\\.(?# Can now capture the point ))+(?# )(?:webm|mov|mp4)(?# ))(?# )\\n?', 'gm') const str = `============================= GOOD TESTS ============================= [download] /root/.local/share/ICONO_TESTS/1678445152615210072_0.33914607510068406/yt-videos/BURGER KLEAN - 1080.mp4 has already been downloaded [download] /root/.local/share/ICONO_TESTS/small/yt-videos/hello.mp4 has already been downloaded [download] /root/local/share/ICONO_TESTS/small/yt-videos/hello.mp4 has already been downloaded Destination: /root/.local/share/ICONO_TESTS/1678445152615210072_0.33914607510068406/yt-videos/Hi Anxiety： Lana Condor - 1080.mp4 [download] Destination: /root/.local/share/ICONO_TESTS/1678445152615210072_0.33914607510068406/yt-videos/#histoire #vrai #fyp #foryou #pourtoi #fyp - NA.mp4 Destination: C:/Users/Adrien/AppData/Local/ICONO/ICONO_TESTS/yt-videos/ICONO in a minute or so. - 1080.webm Destination: C:/Users/Adrien/AppData/Local/ICONO/ICONO_TESTS/yt-videos/ICONO in a minute or so - 1080.webm Destination: C:/Users/Adrien/AppData/Local/ICONO/ICONO_TESTS/yt-videos/ICONO.webm Destination: C:/Users/Adrien/AppData/Local/ICONO/ICONO_TESTS/yt-videos/ICONO_123.webm Destination: C:/Users/Adrien/AppData/Local/ICONO/ICONO_TESTS/yt-videos/ICONO_1.2.3.mp4 xxx Destination: C:/Users/Adrien/AppData/Local/ICONO/ICONO_TESTS/yt-videos/ICONO in a minute or so - 1080.mov xxx Adding metadata to "C:/Users/Adrien/AppData/Local/ICONO/ICONO_TESTS/yt-videos/ICONO in a minute or so - 1080.mov" [Metadata] Adding metadata to "C:/Users/Adrien/AppData/Local/ICONO/ICONO_TESTS/yt-videos/ICONO in a minute or so - 1080.mov" [Metadata] Adding metadata to "C:/Users/Adrien/AppData/Local/ICONO/ICONO_TESTS/yt-videos/ICONO in a minute or so - 1080.mov" [Metadata] Adding metadata to "/home/ezalos/.local/share/ICONO_TESTS/yt-videos/ICONO in a minute or so. - 1080.mov" [Metadata] Adding metadata to "/home/ezalos/.local/share/ICONO_TESTS/yt-videos/ICONO in a minute or so. - 1080.mov" Adding metadata to "C:\\Users\\Adrien\\AppData\\Local\\ICONO\\ICONO_TESTS\\1678715744635004900_0.6505223019081934\\yt-videos\\BURGER KLEAN - 1080.mp4 ============================= BAD TESTS ============================= def test_download(browser: Chrome): app_actions = AppActions(browser, test_name="test_download") app_actions.screenshot() for url in url_to_test: file_path = app_actions.download_video(url) > assert os.path.isfile(file_path) E AssertionError: assert False 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') E + where <function isfile at 0x000002D095AFF160> = <module 'ntpath' from 'C:\\\\Users\\\\Adrien\\\\mambaforge\\\\envs\\\\ICONO-prod\\\\lib\\\\ntpath.py'>.isfile E + where <module 'ntpath' from 'C:\\\\Users\\\\Adrien\\\\mambaforge\\\\envs\\\\ICONO-prod\\\\lib\\\\ntpath.py'> = os.path Destination: C:/Users/Adrien/AppData/Local/ICONO/ICONO_TESTS/yt-videos/ICONO in a minute or so - 1080.f248.webm Destination: C:/Users/Adrien/AppData/Local/ICONO/ICONO_TESTS/yt-videos/ICONO in a minute or so - 1080.f248.mov 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) 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) 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) 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) 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) 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) 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) 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) 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) 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) 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) `; // Reset `lastIndex` if this regex is defined globally // regex.lastIndex = 0; let m; while ((m = regex.exec(str)) !== null) { // This is necessary to avoid infinite loops with zero-width matches if (m.index === regex.lastIndex) { regex.lastIndex++; } // The result can be accessed through the `m`-variable. m.forEach((match, groupIndex) => { console.log(`Found match, group ${groupIndex}: ${match}`); }); }

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 JavaScript, please visit: https://developer.mozilla.org/en/docs/Web/JavaScript/Guide/Regular_Expressions