python - Django 优化方法中的循环

Question

我编写了检查一个属性的方法，如果有一位艺术家的 selling=False 则返回 False，否则返回 True。

def check_selling(track, excludes):
    """
    Returns True if all track's artists are allowed for selling. False otherwise
    """
    for artist in track.artists.all():
            if not artist.selling:
                excludes.append(track.pk)
                return False
    return True

我怎样才能最大限度地减少这种情况？

我试过:

def check_selling(track, excludes):
    res = excludes.append(track.pk) if not [artist.selling for artist in track.artists.all()] else True
    return res or False

但是 [False] 或 [True] 导致列表理解 [artist.selling for artist in track.artists.all()] 总是给出 True...

Answer 1

进行查询! 参见 Here

def check_selling(track, excludes):
    """
    Returns True if all track's artists are allowed for selling. False otherwise
    """
    if track.artists.filter(selling=False).exists(): #If "selling" is a boolean
        excludes.append(track)
        return False
    return True

只有一个查询