Django 计算汇总总数
Django Calculate Aggregated Totals
我正在尝试构建一个 table 来根据用户 ID 汇总统计信息。这是第一次提出问题,如果我遗漏了任何重要问题,请多多包涵。
这是模型:
class Batting(models.Model):
player = models.ForeignKey(
'Player',
on_delete=models.CASCADE,
null=True,
)
game = models.ForeignKey(
'Game',
on_delete=models.CASCADE,
null=True,
blank=True,
)
season = models.ForeignKey(
'Season',
on_delete=models.CASCADE,
null=True,
)
games_played = models.IntegerField(
blank=True,
default=1,
)
plate_appearances = models.IntegerField(
blank=True,
default=0,
)
at_bats = models.DecimalField(
default=0,
max_digits=6,
decimal_places=3,
)
hits = models.DecimalField(
blank=True,
max_digits=6,
decimal_places=3,
default=0,
)
...
batting_average = models.DecimalField(
max_digits=6,
decimal_places=3,
editable=False,
null=True
)
slugging_percentage = models.DecimalField(
max_digits=6,
decimal_places=3,
editable=False,
null=True
)
on_base_percentage = models.DecimalField(
max_digits=6,
decimal_places=3,
editable=False,
null=True
)
on_base_plus_slugging_percentage = models.DecimalField(
max_digits=6,
decimal_places=3,
editable=False,
null=True
)
def save(self, *args, **kwargs):
self.total_bases = self.singles + (self.doubles * 2) + (self.triples * 3) + (self.home_runs * 4)
self.extra_base_hits = self.doubles + self.triples + self.home_runs
self.batting_average = float(self.hits) / float(self.at_bats)
self.slugging_percentage = self.total_bases / float(self.at_bats)
self.on_base_percentage = (self.hits + self.base_on_balls + self.hit_by_pitch) / float(self.at_bats + self.base_on_balls + self.sacrifice_flys + self.hit_by_pitch)
self.on_base_plus_slugging_percentage = (self.hits + self.base_on_balls + self.hit_by_pitch) / float(self.at_bats + self.base_on_balls + self.sacrifice_flys + self.hit_by_pitch)
super(Batting, self).save(*args, **kwargs)
class Meta:
verbose_name = u'Batting Stat'
verbose_name_plural = u'Batting Stats'
def __unicode__(self):
return self.player.last_name
视图如下:
def stats(request):
batting_stats = Batting.objects.values('player__id').annotate(
fn=F('player__first_name'),
ln=F('player__last_name'),
total_hits=Sum(('hits'),output_field=FloatField()),
total_at_bats=Sum(('at_bats'),output_field=FloatField()),
avg=Avg('batting_average'),
slg=Avg('slugging_percentage'),
obp=Avg('on_base_percentage'),
ops=Avg('on_base_plus_slugging_percentage'),
)
return render(request, 'stats.html', {
'batting_stats': batting_stats,
})
我遇到的问题是avg, slg, obp, ops都是模型中的计算,在View中Averaging them是求平均值,而不是计算总计,是根据player ID聚合的.
我试过使用聚合函数,但还没有找到让它工作的方法。有没有一种方法可以结合使用 Annotate 和 Aggregate,使我能够在单个玩家 ID 下整合统计数据并将这些相同的计算应用于总数?
如我所见,实际上您需要对单个击球实例和您的统计视图进行完全相同的计算。所以我将它放在一个函数中并从两点调用它:
def count_averages(data, result_recipient=None):
result_recipient = data if result_recipient=None else result_recipient
result_recipient.total_bases = data.singles + (data.doubles * 2) + (data.triples * 3) + (data.home_runs * 4)
result_recipient.extra_base_hits = data.doubles + data.triples + data.home_runs
...
def save(self, *args, **kwargs):
count_averages(self)
super(Batting, self).save(*args, **kwargs)
def stats(request):
sum_of_all_batting_stats = Batting.objects.filter('player__id'=player__id).annotate(
sum('singles'),
sum('doubles'),
sum('triples'),
...
)
batting_stats = {}
count_averages(self, batting_stats)
return render(request, 'stats.html', {
'batting_stats': batting_stats,
})
这不是 100% 有效的代码,但您应该明白:您将计算移至分离的函数并调用 2 个不同的数据 - 1) 一个击球实例和 2) 所有击球的总和实例。
P.S。如果您每次都为每个视图调用计算它,那可能会导致性能问题。我建议将聚合统计信息存储在数据库 table 或某些缓存中。
我正在尝试构建一个 table 来根据用户 ID 汇总统计信息。这是第一次提出问题,如果我遗漏了任何重要问题,请多多包涵。
这是模型:
class Batting(models.Model):
player = models.ForeignKey(
'Player',
on_delete=models.CASCADE,
null=True,
)
game = models.ForeignKey(
'Game',
on_delete=models.CASCADE,
null=True,
blank=True,
)
season = models.ForeignKey(
'Season',
on_delete=models.CASCADE,
null=True,
)
games_played = models.IntegerField(
blank=True,
default=1,
)
plate_appearances = models.IntegerField(
blank=True,
default=0,
)
at_bats = models.DecimalField(
default=0,
max_digits=6,
decimal_places=3,
)
hits = models.DecimalField(
blank=True,
max_digits=6,
decimal_places=3,
default=0,
)
...
batting_average = models.DecimalField(
max_digits=6,
decimal_places=3,
editable=False,
null=True
)
slugging_percentage = models.DecimalField(
max_digits=6,
decimal_places=3,
editable=False,
null=True
)
on_base_percentage = models.DecimalField(
max_digits=6,
decimal_places=3,
editable=False,
null=True
)
on_base_plus_slugging_percentage = models.DecimalField(
max_digits=6,
decimal_places=3,
editable=False,
null=True
)
def save(self, *args, **kwargs):
self.total_bases = self.singles + (self.doubles * 2) + (self.triples * 3) + (self.home_runs * 4)
self.extra_base_hits = self.doubles + self.triples + self.home_runs
self.batting_average = float(self.hits) / float(self.at_bats)
self.slugging_percentage = self.total_bases / float(self.at_bats)
self.on_base_percentage = (self.hits + self.base_on_balls + self.hit_by_pitch) / float(self.at_bats + self.base_on_balls + self.sacrifice_flys + self.hit_by_pitch)
self.on_base_plus_slugging_percentage = (self.hits + self.base_on_balls + self.hit_by_pitch) / float(self.at_bats + self.base_on_balls + self.sacrifice_flys + self.hit_by_pitch)
super(Batting, self).save(*args, **kwargs)
class Meta:
verbose_name = u'Batting Stat'
verbose_name_plural = u'Batting Stats'
def __unicode__(self):
return self.player.last_name
视图如下:
def stats(request):
batting_stats = Batting.objects.values('player__id').annotate(
fn=F('player__first_name'),
ln=F('player__last_name'),
total_hits=Sum(('hits'),output_field=FloatField()),
total_at_bats=Sum(('at_bats'),output_field=FloatField()),
avg=Avg('batting_average'),
slg=Avg('slugging_percentage'),
obp=Avg('on_base_percentage'),
ops=Avg('on_base_plus_slugging_percentage'),
)
return render(request, 'stats.html', {
'batting_stats': batting_stats,
})
我遇到的问题是avg, slg, obp, ops都是模型中的计算,在View中Averaging them是求平均值,而不是计算总计,是根据player ID聚合的.
我试过使用聚合函数,但还没有找到让它工作的方法。有没有一种方法可以结合使用 Annotate 和 Aggregate,使我能够在单个玩家 ID 下整合统计数据并将这些相同的计算应用于总数?
如我所见,实际上您需要对单个击球实例和您的统计视图进行完全相同的计算。所以我将它放在一个函数中并从两点调用它:
def count_averages(data, result_recipient=None):
result_recipient = data if result_recipient=None else result_recipient
result_recipient.total_bases = data.singles + (data.doubles * 2) + (data.triples * 3) + (data.home_runs * 4)
result_recipient.extra_base_hits = data.doubles + data.triples + data.home_runs
...
def save(self, *args, **kwargs):
count_averages(self)
super(Batting, self).save(*args, **kwargs)
def stats(request):
sum_of_all_batting_stats = Batting.objects.filter('player__id'=player__id).annotate(
sum('singles'),
sum('doubles'),
sum('triples'),
...
)
batting_stats = {}
count_averages(self, batting_stats)
return render(request, 'stats.html', {
'batting_stats': batting_stats,
})
这不是 100% 有效的代码,但您应该明白:您将计算移至分离的函数并调用 2 个不同的数据 - 1) 一个击球实例和 2) 所有击球的总和实例。
P.S。如果您每次都为每个视图调用计算它,那可能会导致性能问题。我建议将聚合统计信息存储在数据库 table 或某些缓存中。