Løst: django rekke datoer

Hovedproblemet med arrays av datoer er at de kan være vanskelige å jobbe med. Datoer er ganske enkelt samlinger av datoer, og kan derfor være vanskelige å manipulere.

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 &lt;b&gt;&lt;i&gt;"my_dates"&lt;/i&gt;&lt;/b&gt;, 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 &lt;b&gt;&lt;i&gt;"my_dates"&lt;/i&gt;&lt;/b&gt; field is called &lt;"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) # fungerer ikke!

MyModel.objects.extra(select={'my_dates': “SELECT * FROM my_dates WHERE my_dates = %s”}, select_params=(date,))

Arbeid med matriser

I Django er matriser en praktisk måte å lagre flere verdier i en enkelt variabel. Arrays kan indekseres og få tilgang til på samme måte som vanlige Python-lister, noe som gjør dem til en ideell datastruktur for små til mellomstore applikasjoner.

For å lage en matrise i Django, bruk array()-funksjonen:

min_matrise = matrise(1, 2, 3)

For å få tilgang til individuelle elementer i en matrise, bruk index()-funksjonen:

print(my_array[0])
utskrifter 1. For å iterere over elementene i en matrise, bruk for-løkken:

for i i my_array: print(i)

Arbeid med datoer

I Django kan du bruke funksjonen work_with() for å administrere datoer. Denne funksjonen tar to argumenter: et datoobjekt og et arbeidsobjekt. Datoobjektet representerer datoen arbeidet skal starte, og arbeidsobjektet representerer oppgaven du vil gjøre på den datoen.

Du kan for eksempel bruke work_with() for å lage en oppgave for i morgen:

work_with(date('i morgen'), task('opprett nytt blogginnlegg') )

Arrays i Django

En array i Django er en samling av objekter. Matriser indekseres fra 0, så en matrise med fem elementer vil bli indeksert som 0, 1, 2, 3, 4.

For å få tilgang til det første elementet i en matrise, bruk indeksen 0. For å få tilgang til det siste elementet i en matrise, bruk indeksen (n-1). For å få tilgang til et hvilket som helst annet element i en matrise, bruk indeksen n.

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