给出以下代码，如果 Buf 已分配给变量，我似乎无法迭代它，除非我将其转换为列表，即使它不是惰性序列。是什么赋予了？
my $file = open $path, bin => True;
$_.chr.say for $file.read: 8; # works well
my $test = $file.read: 8;
$_.chr.say for $test; # fails with "No such method 'chr' for invocant of type 'Buf[uint8]'"
$_.chr.say for $test.list; # works well
$test.is-lazy.say; # False
这：
my %dict;
my $counter = 0;
for ^5 -> $digit {
%dict{$digit} = ($counter,);
$counter += 1;
}
say %dict;
给了我这个：
{0 => (5), 1 => (5), 2 => (5), 3 => (5), 4 => (5)}，但我期望这个：
{0 => (0), 1 => (1), 2 => (2), 3 => (3), 4 => (4)}
分配一个裸值，一个数组或散列按我的预期工作。
我有以下型号:
class Song(models.Model):
name = models.CharField(max_length=64)
def __unicode__(self):
return self.name
class UserProfile(AbstractUser):
current = models.ManyToManyField(Song, related_name="in_current", blank=True)
saved = models.ManyToManyField(Song, related_name="in_saved", blank=True)
whatever = models.ManyToManyField(Song, related_name="in_whatever", blank=True)
def __unicode__(self):
return self.get_username()
以及序列化器:
class SongSerializer(serializers.ModelSerializer):
class Meta:
model = Song
class UserProfileSongsSerializer(serializers.ModelSerializer):
current = SongSerializer(many=True)
saved = SongSerializer(many=True)
whatever = SongSerializer(many=True)
class Meta:
model = UserProfile
fields = ("id", "current", "saved", "whatever")
并且我正在使用UpdateAPIView:
class UserProfileSongsUpdate(generics.UpdateAPIView):
queryset = UserProfile.objects.all()
serializer_class = UserProfileSongsSerializer
问题:我无法将歌曲(即使它已经存在于数据库中)添加到任何(当前,已保存,无论如何),我只能删除它.
curl -X PUT -d '{"current": [{"id": 1, "name": "sialalalal"}, …