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我需要使用 Lua 将一些表示和弦的音符输入转换为高于其根音 0 的数字。

    So from the midi data we get the notes of a C13 Chord 
    input: C, E, G, A#, D, F, A 
    as the root note 0 is C we start on the C note,
    below we have 2 octaves of a piano keyboard, 12 notes on each where chords are played
    0C 1C# 2D 3D# 4E 5F 6F# 7G 8G# 9A 10A# 11B 12C 13C# 14D 15D# 16E 17F 18F# 19G 20G# 21A 22A# 23B
    so C is the root note 0
    D,F,A are played on the next octave
    result: 0,4,7,10,14,17,21

    so if we have a D chord
    input: D,F#,A
    D is the root note 0
    all notes played on the first octave
    0D 1D# 2E 3F 4F# 5G 6G# 7A 8A# 9B 10C 11C# 12D 13D# 14E 15F 16F# 17G 18G# 19A 20A# 21B 22C 23C# 
    result: 0,4,7

    G#m7#9 Chord
    input: G#,B,D#,F#,B
    0G# 1A 2A# 3B 4C 5C# 6D 7D# 8E 9F 10F# 11G 12G# 13A 14A# 15B 16C 17C# 18D 19D# 20E 21F 22F# 23G
    result: 0,3,7,10,15
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1 回答 1

1

像这样的东西可能会起作用：

local function notes2nums(input)
  local map = {A = 9, ["A#"] = 10, B = 11, C = 0, ["C#"] = 1, D = 2, ["D#"] = 3, E = 4, F = 5, ["F#"] = 6, G = 7, ["G#"] = 8}
  local base, prev
  return (input:gsub("([^,]+)", function(note)
        local num = map[note] or error(("Unexpected note value '%s'"):format(note))
        base = base or num
        num = num - base
        if prev and num < prev then num = num + 12 end
        prev = num
        return tostring(num)
      end))
end
print(notes2nums("D,F#,A"))
print(notes2nums("C,E,G,A#,D,F,A"))
print(notes2nums("G#,B,D#,F#,B"))

这打印：

0,4,7
0,4,7,10,14,17,21
0,3,7,10,15
于 2018-07-13T05:42:10.890 回答