Question

so i made this program where it take a guitar tab and gets the fret number and runs it through a dictionary which gets the note and searches for it in the uke note dictionary.

but my probleme is if i have a tab in a txt file ex:

|-----11----------11----------11------11--13--11----------11----------11----------11------11--13--11---------------|
|-------13----------13----------13--------------------------13----------13----------13-----------------------------|
|--13-----13---13-----13---12-----12---------------12-13------13---13-----13---12-----12--------------------------|
|------------------------------------------------------------------------------------------------------------------|
|------------------------------------------------------------------------------------------------------------------|
|------------------------------------------------------------------------------------------------------------------|

So what i would want would be to open the txt file and put a letter in front of each number corosponding with the line. so every number on the first line would have say a “e”,second line:”B” and third:”G”

And have it in order so that the end result would be: G13 e11 B13 G13 etc…
Any ideas?

Answer 1

For the parsing, write a function that takes a line of tabs and a note, that yields the frets along with the position:

import re

def parse_line(line, note):
    fret_pattern = re.compile(r'\d+')
    for match in fret_pattern.finditer(line):
        yield (match.start(), ''.join((note, match.group(0))))

For the first line, |-----11--, this will yield (6, "e11"). The tuples can be used later to sort all notes on all strings.

Now just open() the file, read in the first 6 lines and give them the correct names:

import itertools

notes = ['e', 'B', 'G', 'D', 'A', 'E']
with open('tab.txt') as fp:
    # Read-in 6 lines
    lines = itertools.islice(fp, 0, 6)

    # Holds all the notes.
    frets = []

    # Process the lines, append all notes to frets.
    for note, line in itertools.izip(notes, lines):
       frets.extend(parse_line(line, note))

    # Sort the frets by position.
    frets.sort()

    # Drop the positions.
    frets = [fret for pos, fret in frets]