[英]Python/Django: Creating a simpler list from values_list()
考慮:
>>>jr.operators.values_list('id')
[(1,), (2,), (3,)]
如何進一步簡化為:
['1', '2', '3']
目的:
class ActivityForm(forms.ModelForm):
def __init__(self, *args, **kwargs):
super(ActivityForm, self).__init__(*args, **kwargs)
if self.initial['job_record']:
jr = JobRecord.objects.get(pk=self.initial['job_record'])
# Operators
self.fields['operators'].queryset = jr.operators
# select all operators by default
self.initial['operators'] = jr.operators.values_list('id') # refined as above.
使用Django查詢集的flat=True
構造: https ://docs.djangoproject.com/en/dev/ref/models/querysets/#django.db.models.query.QuerySet.values_list
從文檔中的示例:
>>> Entry.objects.values_list('id', flat=True).order_by('id')
[1, 2, 3, ...]
您需要執行..以獲取此輸出['1','2','3']
map(str, Entry.objects.values_list('id', flat=True).order_by('id'))
您可以使用列表理解:
>>> mylist = [(1,), (2,), (3,)] >>> [str(x[0]) for x in mylist] ['1', '2', '3']
像這樣嗎
x = [(1,), (2,), (3,)]
y = [str(i[0]) for i in x]
['1', '2', '3']
從平面查詢集轉換:
Entry.objects.values_list('id', flat=True)
<QuerySet [1, 5]>
到 Python 列表,你可以這樣做:
[*Entry.objects.values_list('id', flat=True)]
[1, 5]
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