fast5_to_fastq.py 文件源码

def get_min_window_qscore(quals, window_size):
    """
    Returns the minimum mean qscore over a sliding window.
    """
    quals = [q - 33 for q in quals]  # covert to numbers
    current_window_qscore = statistics.mean(quals[:window_size])
    shift_count = len(quals) - window_size
    if shift_count < 1:
        return current_window_qscore
    min_window_qscore = current_window_qscore
    for i in range(shift_count):
        leaving_window = quals[i]
        entering_window = quals[i + window_size]
        current_window_qscore += (entering_window - leaving_window) / window_size
        if current_window_qscore < min_window_qscore:
            min_window_qscore = current_window_qscore
    return min_window_qscore