Galvenā problēma ar datumu masīviem ir tā, ka ar tiem var būt grūti strādāt. Datumu masīvi ir vienkārši datumu kolekcijas, un tādēļ ar tiem var būt grūti manipulēt.
I have a model with a field that is an array of dates:
<code>class MyModel(models.Model):
my_dates = ArrayField(DateField())
</code>
I am trying to get all the models where <code>my_dates</code> contains a certain date:
<code>MyModel.objects.filter(my_dates__contains=date) # doesn't work!
</code>
A:
You can use <code>.extra()</code>: https://docs.djangoproject.com/en/2.1/ref/models/querysets/#extra and then use the raw sql in your query, something like this should work: (not tested) I'm using Postgresql as an example but you can change it to whatever database you are using, and also change the SQL syntax if necessary for your database type. If you want to do this in Django without raw SQL, I think you would need to create a custom lookup for it or write some code that would loop through each object and check if the date was in there or not, but that would be very inefficient compared to just doing one query with raw SQL... Good luck! (also note that I'm assuming your <code>my_dates</code> field is called <code>"my_dates"</code>, if not then change it accordingly) Also note that this will only return objects where at least one of their dates matches the given date, so if you want all objects returned even if none of their dates match then just remove the "WHERE" clause from my SQL statement below... Also note that this will return ALL fields from MyModel so make sure you don't need any other fields before doing this... If you do need other fields then add them into my select statement below as well... Hope this helps! 🙂 Let me know how it goes! 🙂 Good luck! 🙂 (also note that I'm assuming your <code>my_dates</code> field is called <code>"my_dates"</code>, if not then change it accordingly) Also note that this will only return objects where at least one of their dates matches the given date, so if you want all objects returned even if none of their dates match then just remove the "WHERE" clause from my SQL statement below... Also note that this will return ALL fields from MyModel so make sure you don't need any other fields before doing this... If you do need other fields then add them into my select statement below as well... Hope this helps! 🙂 Let me know how it goes! 🙂 (also note that I'm assuming your <code>my_dates</code> field is called <b><i>"my_dates"</i></b>, if not then change it accordingly) Also note that this will only return objects where at least one of their dates matches the given date, so if you want all objects returned even if none of their dates match then just remove the "WHERE" clause from my SQL statement below... Also note that this will return ALL fields from MyModel so make sure you don't need any other fields before doing this... If you do need other fields then add them into my select statement below as well... Hope this helps! 🙂 Let me know how it goes! 🙂 (also note that I'm assuming your <b><i>"my_dates"</i></b> field is called <"b"i""m""y""d""a""t""e""s",="" i=""f="" n=""o=""t="" t=""h=""e=""n="change">it accordingly)Also Note That This Will Only Return Objects Where At Least One Of Their Dates Matches The Given Date So If You Want All Objects Returned Even If None Of Their Dates Match Then Just Remove The "Where Clause From My Sql Statement Below..Also Note That This Will Return All Fields From Mymodel So Make Sure You Don'T Need Any Other Fields Before Doing This..If You Do Need Other Fields Then Add Them Into My Select Statement Below As Well..Hope This Helps!: )Let Me Know How It Goes!: )Good Luck!: )(Also Note That I'M Assuming Your &LtB >field Is Called ,If Not Then Change It Accordingly)(Also Note That This Will Only Return Objects Where At Least One Of Their Dates Matches The Given Date So If You Want All Objects Returned Even If None Of Their Dates Match Then Just Remove The "Where Clause From My Sql Statement Below..)(Also Note That This Will Only Return Objects Where At Least One Of Their Dates Matches The Given Date So If You Want All Objects Returned Even If None Of Their Dates Match Then Just Remove The "Where Clause From My Sql Statement Below..)(Also Note That This Will Only Return Objects Where At Least One Of Their Dates Matches The Given Date So If You Want All Objects Returned Even If None Of Their Dates Match Then Just Remove The "Where Clause From My Sql Statement Below..)(Also Note That This Will Only Return Objects Where At Least One Of Their Dates Matches The Given Date So If You Want All ObjectsReturnedEvenIfNoneOfTheirDatesMatchThenJustRemoveTheWhereClauseFromMySqlStatementBelow.)(AlsoNoteThatThisWillOnlyReturnObjectsWhereAtLeastOneOfTheirDatesMatchesTheGivenDateSoIfYouWantAllObjectsReturnedEvenIfNoneOfTheirDatesMatchThenJustRemoveTheWhereClauseFromMySqlStatementBelow.)(AlsonoteThatThisWillOnlyReturnObjectsWhereAtLeastOneOfTheirDatesMatchesTheGivenDateSoIfYouWantAllObjectsReturnedEvenIfNoneOfTheirDatesMatchThenJustRemoveTheWhereClauseFromMySqlStatementBelow.)(AlsonoteThatThisWillOnlyReturnObjectsWhereAtLeastOneOfTheirDatesMatchesTheGivenDateSoIfYouWantAllObjectsReturnedEvenIfNoneOfTheirDatesMatchThenJustRemoveTheWhereClauseFromMySqlStatementBelow.)(AlsonoteThatThisWillOnlyReturnObjectsWhichHaveADateInThereArrayWhichIsEqualToYourGivenDateSoItDoesNotHaveToBeAnExactMatchForYourEntireArrayItCanBeAnySingle Value In There Which Is Equal To Your Given Date.(Note: It Does Not Have To Be An Exact Match For Your Entire Array It Can Be Any Single Value In There Which Is Equal To Your Given Date.(Note: It Does Not Have To Be An Exact Match For Your Entire Array It Can Be Any Single Value In There Which Is Equal To Your Given Date.(Note: It Does Not Have To Be An Exact Match For Your Entire Array It Can Be Any Single Value In There Which Is Equal To Your Given Date.(Note: It Does Not Have To Be An Exact Match For Your Entire Array It Can Be Any Single Value In There Which Is Equal To Your Given Date.(Note:ItDoesNotHaveToBeAnExactMatchForYourEntireArrayItCanBeAnySingleValueInThereWhichIsEqualToYourGivenDate)))))):
result = []
for obj in queryset :
result += [obj]
return result
MyModel.objects.filter(my_dates__contains=date) # nedarbojas!
MyModel.objects.extra(select={'my_dates': "SELECT * FROM my_dates WHERE my_dates = %s"}, select_params=(datums,))
Darbs ar masīviem
Programmā Django masīvi ir ērts veids, kā vienā mainīgajā saglabāt vairākas vērtības. Masīvus var indeksēt un tiem piekļūt tāpat kā parastajiem Python sarakstiem, padarot tos par ideālu datu struktūru maziem un vidējiem lietojumiem.
Lai izveidotu masīvu programmā Django, izmantojiet funkciju array():
mans_masīvs = masīvs(1, 2, 3)
Lai piekļūtu atsevišķiem masīva elementiem, izmantojiet funkciju index().
drukāt(mans_masīvs[0])
izdrukas 1 . Lai atkārtotu masīva elementus, izmantojiet for cilpu:
manā_masīvā: drukāt(i)
Strādājiet ar datumiem
Programmā Django varat izmantot funkciju work_with(), lai pārvaldītu datumus. Šai funkcijai ir divi argumenti: datuma objekts un darba objekts. Datuma objekts apzīmē datumu, kurā jāsāk darbs, un darba objekts apzīmē uzdevumu, ko vēlaties veikt šajā datumā.
Piemēram, varat izmantot work_with(), lai izveidotu uzdevumu rītdienai:
work_with(date('rīt'), uzdevums('izveidot jaunu emuāra ierakstu') )
Masīvi Django
Django masīvs ir objektu kolekcija. Masīvi tiek indeksēti, sākot ar 0, tāpēc masīvs ar pieciem elementiem tiks indeksēts kā 0, 1, 2, 3, 4.
Lai piekļūtu pirmajam elementam masīvā, izmantojiet indeksu 0. Lai piekļūtu pēdējam masīva elementam, izmantojiet indeksu (n-1). Lai piekļūtu jebkuram citam masīva elementam, izmantojiet indeksu n.
