El principal problema con las matrices de fechas es que puede ser difícil trabajar con ellas. Las matrices de fechas son simplemente colecciones de fechas y, como tales, pueden ser difíciles de manipular.
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) # ¡no funciona!
MyModel.objects.extra(select={'my_dates': “SELECT * FROM my_dates WHERE my_dates = %s”}, select_params=(date,))
Trabajar con arreglos
En Django, las matrices son una forma conveniente de almacenar múltiples valores en una sola variable. Se puede indexar y acceder a los arreglos de la misma manera que las listas regulares de Python, lo que los convierte en una estructura de datos ideal para aplicaciones de tamaño pequeño a mediano.
Para crear una matriz en Django, use la función array():
mi_matriz = matriz(1, 2, 3)
Para acceder a elementos individuales de una matriz, utilice la función index():
imprimir (mi_matriz [0])
imprime 1 . Para iterar sobre los elementos de una matriz, use el bucle for:
for i en my_array: print(i)
Trabajar con fechas
En Django, puede usar la función work_with() para administrar las fechas. Esta función toma dos argumentos: un objeto de fecha y un objeto de trabajo. El objeto de fecha representa la fecha en que debe comenzar el trabajo y el objeto de trabajo representa la tarea que desea realizar en esa fecha.
Por ejemplo, puede usar work_with() para crear una tarea para mañana:
work_with(fecha('mañana'), tarea('crear nueva publicación de blog') )
Matrices en Django
Una matriz en Django es una colección de objetos. Las matrices se indexan a partir de 0, por lo que una matriz con cinco elementos se indexaría como 0, 1, 2, 3, 4.
Para acceder al primer elemento de una matriz, utilice el índice 0. Para acceder al último elemento de una matriz, utilice el índice (n-1). Para acceder a cualquier otro elemento de una matriz, utilice el índice n.
