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kennethreitz
9da3ac8b28
- circle_of_fifths.py — visualize keys around the circle - chord_identifier.py — identify chords from notes and fingerings - key_explorer.py — explore keys, signatures, progressions, borrowed chords - temperament_comparison.py — compare equal, Pythagorean, and meantone - chord_tension.py — analyze tension, consonance, and voice leading - world_scales.py — scales from 6 musical traditions - fretboard_explorer.py — instruments, tunings, capo transposition - midi_converter.py — MIDI ↔ note ↔ frequency reference - progression_writer.py — famous progressions, Nashville numbers, random generation - interval_trainer.py — interval names, songs, and consonance ranking - overtone_series.py — harmonics and why chords sound good - key_detection.py — detect keys from melodies and chord progressions Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
65 lines
2.2 KiB
Python
65 lines
2.2 KiB
Python
"""Detect the key of a melody or chord progression."""
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from pytheory import Key, Chord
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print("Key Detection")
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print("=" * 55)
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print()
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# ── Detect from Melody Notes ────────────────────────────────────────────
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melodies = [
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("Twinkle Twinkle", ["C", "G", "A", "F", "E", "D"]),
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("Happy Birthday", ["G", "A", "B", "C", "D", "F#"]),
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("Yesterday", ["F", "E", "D", "C", "Bb", "A", "G"]),
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("Minor melody", ["A", "B", "C", "D", "E", "F", "G"]),
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("Blues lick", ["E", "G", "A", "B", "D"]),
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("Chromatic fragment", ["C", "C#", "D", "D#", "E"]),
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]
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print("Detecting key from melody notes:")
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print()
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for label, notes in melodies:
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key = Key.detect(*notes)
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print(f" {label:22s} {', '.join(notes):30s} → {key}")
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# ── Detect from Chord Progression ──────────────────────────────────────
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print()
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print("Detecting key from chord tones:")
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print()
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progressions = [
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("I-IV-V", [("C", "E", "G"), ("F", "A", "C"), ("G", "B", "D")]),
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("Pop in G", [("G", "B", "D"), ("D", "F#", "A"), ("E", "G", "B"), ("C", "E", "G")]),
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("Jazz ii-V-I", [("D", "F", "A"), ("G", "B", "D", "F"), ("C", "E", "G", "B")]),
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]
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for label, chord_tones in progressions:
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# Collect all unique note names
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all_notes = set()
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for tones in chord_tones:
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all_notes.update(tones)
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key = Key.detect(*all_notes)
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chord_names = [Chord.from_tones(*t).identify() for t in chord_tones]
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print(f" {label:15s} {' → '.join(chord_names):40s} → {key}")
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# ── All 24 Keys ─────────────────────────────────────────────────────────
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print()
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print("All 24 Major and Minor Keys")
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print("=" * 55)
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print()
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for key in Key.all_keys():
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sig = key.signature
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acc = ", ".join(sig["accidentals"]) if sig["accidentals"] else "none"
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rel = key.relative
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print(
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f" {str(key):12s} "
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f"{sig['sharps']}# {sig['flats']}b "
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f"({acc:15s}) "
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f"rel: {rel}"
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)
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