def pad(well, padded=True):
    """Converts to or from zero-padded column names
    (e.g., A1 <-> A01)
    """
    # Get row and column
    row = well[0]
    col = well[1:]

    # Convert to int then to str (gives non-padded)
    col = str(int(col))

    # Pad
    if padded:
        if len(col) == 1:
            col = '0'+col

    well = row+col
    
    return well