data = [[1.1, 34,2342,234,234,234],
        [1.2, 34,2342,234,234,234],
        [1.3, 34,2342,234,234,234]]
mode = 'second'

def function(self, data, mode):
    sr = 0.1
    new_index = data[0][0]
    fixed_data = []
    i = 0
    while i < len(data) - 2:
        while new_index > data[i + 1][0]:
            new_row = copy.copy(data[i])
            new_row[0] = new_index
            fixed_data.append(new_row)
            if mode == 'first':
                new_index -= sr
            elif mode == 'second':
                new_index += sr
            continue
        if abs(data[i + 1][0] - new_index) < abs(data[i + 2][0] - new_index):
            new_row = copy.copy(data[i + 1])
            new_row[0] = new_index
            i += 1 # changed
        else:
            new_row = copy.copy(data[i + 2])
            new_row[0] = new_index
            i += 1
        fixed_data.append(new_row)
        if mode == 'first':
            new_index -= sr
        elif mode == 'second':
            new_index += sr
    return fixed_data