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[4.2.x] Refs #34140 -- Applied rst code-block to non-Python examples.
Thanks to J.V. Zammit, Paolo Melchiorre, and Mariusz Felisiak for
reviews.
Backport of 534ac48297 from main.
This commit is contained in:
Carlton Gibson
committed by
Mariusz Felisiak
Mariusz Felisiak
parent
4a89aa25c9
commit
b784768eef
@@ -35,7 +35,9 @@ Comparison and conversion functions
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Forces the result type of ``expression`` to be the one from ``output_field``.
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Usage example::
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Usage example:
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.. code-block:: pycon
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>>> from django.db.models import FloatField
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>>> from django.db.models.functions import Cast
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@@ -56,7 +58,9 @@ first non-null value (note that an empty string is not considered a null
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value). Each argument must be of a similar type, so mixing text and numbers
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will result in a database error.
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Usage examples::
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Usage examples:
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.. code-block:: pycon
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>>> # Get a screen name from least to most public
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>>> from django.db.models import Sum
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@@ -99,12 +103,16 @@ Usage examples::
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Takes an expression and a collation name to query against.
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For example, to filter case-insensitively in SQLite::
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For example, to filter case-insensitively in SQLite:
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.. code-block:: pycon
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>>> Author.objects.filter(name=Collate(Value('john'), 'nocase'))
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<QuerySet [<Author: John>, <Author: john>]>
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It can also be used when ordering, for example with PostgreSQL::
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It can also be used when ordering, for example with PostgreSQL:
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.. code-block:: pycon
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>>> Author.objects.order_by(Collate('name', 'et-x-icu'))
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<QuerySet [<Author: Ursula>, <Author: Veronika>, <Author: Ülle>]>
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@@ -129,6 +137,8 @@ Usage example::
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modified = models.DateTimeField(auto_now=True)
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blog = models.ForeignKey(Blog, on_delete=models.CASCADE)
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.. code-block:: pycon
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>>> from django.db.models.functions import Greatest
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>>> blog = Blog.objects.create(body='Greatest is the best.')
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>>> comment = Comment.objects.create(body='No, Least is better.', blog=blog)
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@@ -159,7 +169,9 @@ and ``comment.modified``.
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Takes a list of key-value pairs and returns a JSON object containing those
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pairs.
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Usage example::
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Usage example:
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.. code-block:: pycon
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>>> from django.db.models import F
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>>> from django.db.models.functions import JSONObject, Lower
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@@ -272,7 +284,9 @@ returned when this timezone is active will be the same as above except for:
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databases and from Python's standard functions. This function will return
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``1`` for Sunday, ``2`` for Monday, through ``7`` for Saturday.
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The equivalent calculation in Python is::
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The equivalent calculation in Python is:
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.. code-block:: pycon
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>>> from datetime import datetime
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>>> dt = datetime(2015, 6, 15)
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@@ -292,7 +306,9 @@ Each ``lookup_name`` above has a corresponding ``Extract`` subclass (listed
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below) that should typically be used instead of the more verbose equivalent,
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e.g. use ``ExtractYear(...)`` rather than ``Extract(..., lookup_name='year')``.
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Usage example::
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Usage example:
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.. code-block:: pycon
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>>> from datetime import datetime
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>>> from django.db.models.functions import Extract
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@@ -356,7 +372,9 @@ class is also a ``Transform`` registered on ``DateField`` and ``DateTimeField``
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as ``__(lookup_name)``, e.g. ``__year``.
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Since ``DateField``\s don't have a time component, only ``Extract`` subclasses
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that deal with date-parts can be used with ``DateField``::
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that deal with date-parts can be used with ``DateField``:
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.. code-block:: pycon
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>>> from datetime import datetime, timezone
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>>> from django.db.models.functions import (
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@@ -406,7 +424,9 @@ These are logically equivalent to ``Extract('datetime_field', lookup_name)``.
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Each class is also a ``Transform`` registered on ``DateTimeField`` as
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``__(lookup_name)``, e.g. ``__minute``.
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``DateTimeField`` examples::
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``DateTimeField`` examples:
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.. code-block:: pycon
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>>> from datetime import datetime, timezone
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>>> from django.db.models.functions import (
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@@ -443,7 +463,9 @@ When :setting:`USE_TZ` is ``True`` then datetimes are stored in the database
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in UTC. If a different timezone is active in Django, the datetime is converted
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to that timezone before the value is extracted. The example below converts to
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the Melbourne timezone (UTC +10:00), which changes the day, weekday, and hour
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values that are returned::
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values that are returned:
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.. code-block:: pycon
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>>> from django.utils import timezone
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>>> import zoneinfo
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@@ -460,7 +482,9 @@ values that are returned::
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{'day': 16, 'weekday': 3, 'isoweekday': 2, 'hour': 9}
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Explicitly passing the timezone to the ``Extract`` function behaves in the same
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way, and takes priority over an active timezone::
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way, and takes priority over an active timezone:
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.. code-block:: pycon
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>>> import zoneinfo
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>>> melb = zoneinfo.ZoneInfo('Australia/Melbourne')
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@@ -482,7 +506,9 @@ way, and takes priority over an active timezone::
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Returns the database server's current date and time when the query is executed,
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typically using the SQL ``CURRENT_TIMESTAMP``.
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Usage example::
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Usage example:
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.. code-block:: pycon
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>>> from django.db.models.functions import Now
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>>> Article.objects.filter(published__lte=Now())
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@@ -566,7 +592,9 @@ The subclasses are all defined as transforms, but they aren't registered with
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any fields, because the lookup names are already reserved by the ``Extract``
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subclasses.
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Usage example::
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Usage example:
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.. code-block:: pycon
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>>> from datetime import datetime
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>>> from django.db.models import Count, DateTimeField
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@@ -622,7 +650,9 @@ with less precision. ``expression`` can have an ``output_field`` of either
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``DateField`` or ``DateTimeField``.
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Since ``DateField``\s don't have a time component, only ``Trunc`` subclasses
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that deal with date-parts can be used with ``DateField``::
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that deal with date-parts can be used with ``DateField``:
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.. code-block:: pycon
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>>> from datetime import datetime, timezone
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>>> from django.db.models import Count
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@@ -700,7 +730,9 @@ truncate all parts of the date up to ``kind`` and allow grouping or filtering
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datetimes with less precision. ``expression`` must have an ``output_field`` of
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``DateTimeField``.
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Usage example::
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Usage example:
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.. code-block:: pycon
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>>> from datetime import date, datetime, timezone
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>>> from django.db.models import Count
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@@ -753,7 +785,9 @@ with less precision. ``expression`` can have an ``output_field`` of either
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``TimeField`` or ``DateTimeField``.
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Since ``TimeField``\s don't have a date component, only ``Trunc`` subclasses
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that deal with time-parts can be used with ``TimeField``::
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that deal with time-parts can be used with ``TimeField``:
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.. code-block:: pycon
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>>> from datetime import datetime, timezone
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>>> from django.db.models import Count, TimeField
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@@ -802,7 +836,9 @@ We'll be using the following model in math function examples::
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Returns the absolute value of a numeric field or expression.
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Usage example::
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Usage example:
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.. code-block:: pycon
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>>> from django.db.models.functions import Abs
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>>> Vector.objects.create(x=-0.5, y=1.1)
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@@ -810,7 +846,9 @@ Usage example::
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>>> vector.x_abs, vector.y_abs
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(0.5, 1.1)
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It can also be registered as a transform. For example::
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It can also be registered as a transform. For example:
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.. code-block:: pycon
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>>> from django.db.models import FloatField
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>>> from django.db.models.functions import Abs
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@@ -826,7 +864,9 @@ It can also be registered as a transform. For example::
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Returns the arccosine of a numeric field or expression. The expression value
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must be within the range -1 to 1.
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Usage example::
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Usage example:
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.. code-block:: pycon
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>>> from django.db.models.functions import ACos
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>>> Vector.objects.create(x=0.5, y=-0.9)
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@@ -834,7 +874,9 @@ Usage example::
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>>> vector.x_acos, vector.y_acos
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(1.0471975511965979, 2.6905658417935308)
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It can also be registered as a transform. For example::
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It can also be registered as a transform. For example:
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.. code-block:: pycon
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>>> from django.db.models import FloatField
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>>> from django.db.models.functions import ACos
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@@ -850,7 +892,9 @@ It can also be registered as a transform. For example::
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Returns the arcsine of a numeric field or expression. The expression value must
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be in the range -1 to 1.
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Usage example::
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Usage example:
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.. code-block:: pycon
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>>> from django.db.models.functions import ASin
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>>> Vector.objects.create(x=0, y=1)
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@@ -858,7 +902,9 @@ Usage example::
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>>> vector.x_asin, vector.y_asin
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(0.0, 1.5707963267948966)
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It can also be registered as a transform. For example::
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It can also be registered as a transform. For example:
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.. code-block:: pycon
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>>> from django.db.models import FloatField
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>>> from django.db.models.functions import ASin
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@@ -873,7 +919,9 @@ It can also be registered as a transform. For example::
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Returns the arctangent of a numeric field or expression.
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Usage example::
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Usage example:
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.. code-block:: pycon
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>>> from django.db.models.functions import ATan
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>>> Vector.objects.create(x=3.12, y=6.987)
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@@ -881,7 +929,9 @@ Usage example::
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>>> vector.x_atan, vector.y_atan
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(1.2606282660069106, 1.428638798133829)
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It can also be registered as a transform. For example::
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It can also be registered as a transform. For example:
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.. code-block:: pycon
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>>> from django.db.models import FloatField
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>>> from django.db.models.functions import ATan
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@@ -896,7 +946,9 @@ It can also be registered as a transform. For example::
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Returns the arctangent of ``expression1 / expression2``.
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Usage example::
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Usage example:
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.. code-block:: pycon
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>>> from django.db.models.functions import ATan2
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>>> Vector.objects.create(x=2.5, y=1.9)
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@@ -912,7 +964,9 @@ Usage example::
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Returns the smallest integer greater than or equal to a numeric field or
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expression.
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Usage example::
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Usage example:
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.. code-block:: pycon
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>>> from django.db.models.functions import Ceil
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>>> Vector.objects.create(x=3.12, y=7.0)
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@@ -920,7 +974,9 @@ Usage example::
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>>> vector.x_ceil, vector.y_ceil
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(4.0, 7.0)
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It can also be registered as a transform. For example::
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It can also be registered as a transform. For example:
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.. code-block:: pycon
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>>> from django.db.models import FloatField
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>>> from django.db.models.functions import Ceil
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@@ -935,7 +991,9 @@ It can also be registered as a transform. For example::
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Returns the cosine of a numeric field or expression.
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Usage example::
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Usage example:
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.. code-block:: pycon
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>>> from django.db.models.functions import Cos
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>>> Vector.objects.create(x=-8.0, y=3.1415926)
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@@ -943,7 +1001,9 @@ Usage example::
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>>> vector.x_cos, vector.y_cos
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(-0.14550003380861354, -0.9999999999999986)
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It can also be registered as a transform. For example::
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It can also be registered as a transform. For example:
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.. code-block:: pycon
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>>> from django.db.models import FloatField
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>>> from django.db.models.functions import Cos
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@@ -958,7 +1018,9 @@ It can also be registered as a transform. For example::
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Returns the cotangent of a numeric field or expression.
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Usage example::
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Usage example:
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.. code-block:: pycon
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>>> from django.db.models.functions import Cot
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>>> Vector.objects.create(x=12.0, y=1.0)
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@@ -966,7 +1028,9 @@ Usage example::
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>>> vector.x_cot, vector.y_cot
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(-1.5726734063976826, 0.642092615934331)
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It can also be registered as a transform. For example::
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It can also be registered as a transform. For example:
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.. code-block:: pycon
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>>> from django.db.models import FloatField
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>>> from django.db.models.functions import Cot
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@@ -981,7 +1045,9 @@ It can also be registered as a transform. For example::
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Converts a numeric field or expression from radians to degrees.
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Usage example::
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Usage example:
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.. code-block:: pycon
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>>> from django.db.models.functions import Degrees
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>>> Vector.objects.create(x=-1.57, y=3.14)
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@@ -989,7 +1055,9 @@ Usage example::
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>>> vector.x_d, vector.y_d
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(-89.95437383553924, 179.9087476710785)
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It can also be registered as a transform. For example::
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It can also be registered as a transform. For example:
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.. code-block:: pycon
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>>> from django.db.models import FloatField
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>>> from django.db.models.functions import Degrees
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@@ -1005,7 +1073,9 @@ It can also be registered as a transform. For example::
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Returns the value of ``e`` (the natural logarithm base) raised to the power of
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a numeric field or expression.
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Usage example::
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Usage example:
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.. code-block:: pycon
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>>> from django.db.models.functions import Exp
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>>> Vector.objects.create(x=5.4, y=-2.0)
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@@ -1013,7 +1083,9 @@ Usage example::
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>>> vector.x_exp, vector.y_exp
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(221.40641620418717, 0.1353352832366127)
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It can also be registered as a transform. For example::
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It can also be registered as a transform. For example:
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.. code-block:: pycon
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>>> from django.db.models import FloatField
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>>> from django.db.models.functions import Exp
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@@ -1029,7 +1101,9 @@ It can also be registered as a transform. For example::
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Returns the largest integer value not greater than a numeric field or
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expression.
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Usage example::
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Usage example:
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.. code-block:: pycon
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>>> from django.db.models.functions import Floor
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>>> Vector.objects.create(x=5.4, y=-2.3)
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@@ -1037,7 +1111,9 @@ Usage example::
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>>> vector.x_floor, vector.y_floor
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(5.0, -3.0)
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It can also be registered as a transform. For example::
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It can also be registered as a transform. For example:
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.. code-block:: pycon
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>>> from django.db.models import FloatField
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>>> from django.db.models.functions import Floor
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@@ -1052,7 +1128,9 @@ It can also be registered as a transform. For example::
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Returns the natural logarithm a numeric field or expression.
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Usage example::
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Usage example:
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.. code-block:: pycon
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>>> from django.db.models.functions import Ln
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>>> Vector.objects.create(x=5.4, y=233.0)
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@@ -1060,7 +1138,9 @@ Usage example::
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>>> vector.x_ln, vector.y_ln
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(1.6863989535702288, 5.4510384535657)
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It can also be registered as a transform. For example::
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It can also be registered as a transform. For example:
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.. code-block:: pycon
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>>> from django.db.models import FloatField
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>>> from django.db.models.functions import Ln
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@@ -1076,7 +1156,9 @@ It can also be registered as a transform. For example::
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Accepts two numeric fields or expressions and returns the logarithm of
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the first to base of the second.
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Usage example::
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Usage example:
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.. code-block:: pycon
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>>> from django.db.models.functions import Log
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>>> Vector.objects.create(x=2.0, y=4.0)
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@@ -1092,7 +1174,9 @@ Usage example::
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Accepts two numeric fields or expressions and returns the remainder of
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the first divided by the second (modulo operation).
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Usage example::
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Usage example:
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.. code-block:: pycon
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>>> from django.db.models.functions import Mod
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>>> Vector.objects.create(x=5.4, y=2.3)
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@@ -1115,7 +1199,9 @@ Returns the value of the mathematical constant ``π``.
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Accepts two numeric fields or expressions and returns the value of the first
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raised to the power of the second.
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Usage example::
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Usage example:
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.. code-block:: pycon
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>>> from django.db.models.functions import Power
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>>> Vector.objects.create(x=2, y=-2)
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@@ -1130,7 +1216,9 @@ Usage example::
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Converts a numeric field or expression from degrees to radians.
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Usage example::
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Usage example:
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.. code-block:: pycon
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>>> from django.db.models.functions import Radians
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>>> Vector.objects.create(x=-90, y=180)
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@@ -1138,7 +1226,9 @@ Usage example::
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>>> vector.x_r, vector.y_r
|
||||
(-1.5707963267948966, 3.141592653589793)
|
||||
|
||||
It can also be registered as a transform. For example::
|
||||
It can also be registered as a transform. For example:
|
||||
|
||||
.. code-block:: pycon
|
||||
|
||||
>>> from django.db.models import FloatField
|
||||
>>> from django.db.models.functions import Radians
|
||||
@@ -1162,7 +1252,9 @@ Rounds a numeric field or expression to ``precision`` (must be an integer)
|
||||
decimal places. By default, it rounds to the nearest integer. Whether half
|
||||
values are rounded up or down depends on the database.
|
||||
|
||||
Usage example::
|
||||
Usage example:
|
||||
|
||||
.. code-block:: pycon
|
||||
|
||||
>>> from django.db.models.functions import Round
|
||||
>>> Vector.objects.create(x=5.4, y=-2.37)
|
||||
@@ -1170,7 +1262,9 @@ Usage example::
|
||||
>>> vector.x_r, vector.y_r
|
||||
(5.0, -2.4)
|
||||
|
||||
It can also be registered as a transform. For example::
|
||||
It can also be registered as a transform. For example:
|
||||
|
||||
.. code-block:: pycon
|
||||
|
||||
>>> from django.db.models import FloatField
|
||||
>>> from django.db.models.functions import Round
|
||||
@@ -1185,7 +1279,9 @@ It can also be registered as a transform. For example::
|
||||
|
||||
Returns the sign (-1, 0, 1) of a numeric field or expression.
|
||||
|
||||
Usage example::
|
||||
Usage example:
|
||||
|
||||
.. code-block:: pycon
|
||||
|
||||
>>> from django.db.models.functions import Sign
|
||||
>>> Vector.objects.create(x=5.4, y=-2.3)
|
||||
@@ -1193,7 +1289,9 @@ Usage example::
|
||||
>>> vector.x_sign, vector.y_sign
|
||||
(1, -1)
|
||||
|
||||
It can also be registered as a transform. For example::
|
||||
It can also be registered as a transform. For example:
|
||||
|
||||
.. code-block:: pycon
|
||||
|
||||
>>> from django.db.models import FloatField
|
||||
>>> from django.db.models.functions import Sign
|
||||
@@ -1208,7 +1306,9 @@ It can also be registered as a transform. For example::
|
||||
|
||||
Returns the sine of a numeric field or expression.
|
||||
|
||||
Usage example::
|
||||
Usage example:
|
||||
|
||||
.. code-block:: pycon
|
||||
|
||||
>>> from django.db.models.functions import Sin
|
||||
>>> Vector.objects.create(x=5.4, y=-2.3)
|
||||
@@ -1216,7 +1316,9 @@ Usage example::
|
||||
>>> vector.x_sin, vector.y_sin
|
||||
(-0.7727644875559871, -0.7457052121767203)
|
||||
|
||||
It can also be registered as a transform. For example::
|
||||
It can also be registered as a transform. For example:
|
||||
|
||||
.. code-block:: pycon
|
||||
|
||||
>>> from django.db.models import FloatField
|
||||
>>> from django.db.models.functions import Sin
|
||||
@@ -1231,7 +1333,9 @@ It can also be registered as a transform. For example::
|
||||
|
||||
Returns the square root of a nonnegative numeric field or expression.
|
||||
|
||||
Usage example::
|
||||
Usage example:
|
||||
|
||||
.. code-block:: pycon
|
||||
|
||||
>>> from django.db.models.functions import Sqrt
|
||||
>>> Vector.objects.create(x=4.0, y=12.0)
|
||||
@@ -1239,7 +1343,9 @@ Usage example::
|
||||
>>> vector.x_sqrt, vector.y_sqrt
|
||||
(2.0, 3.46410)
|
||||
|
||||
It can also be registered as a transform. For example::
|
||||
It can also be registered as a transform. For example:
|
||||
|
||||
.. code-block:: pycon
|
||||
|
||||
>>> from django.db.models import FloatField
|
||||
>>> from django.db.models.functions import Sqrt
|
||||
@@ -1254,7 +1360,9 @@ It can also be registered as a transform. For example::
|
||||
|
||||
Returns the tangent of a numeric field or expression.
|
||||
|
||||
Usage example::
|
||||
Usage example:
|
||||
|
||||
.. code-block:: pycon
|
||||
|
||||
>>> from django.db.models.functions import Tan
|
||||
>>> Vector.objects.create(x=0, y=12)
|
||||
@@ -1262,7 +1370,9 @@ Usage example::
|
||||
>>> vector.x_tan, vector.y_tan
|
||||
(0.0, -0.6358599286615808)
|
||||
|
||||
It can also be registered as a transform. For example::
|
||||
It can also be registered as a transform. For example:
|
||||
|
||||
.. code-block:: pycon
|
||||
|
||||
>>> from django.db.models import FloatField
|
||||
>>> from django.db.models.functions import Tan
|
||||
@@ -1287,7 +1397,9 @@ function.
|
||||
Like :class:`Length`, it can be registered as a transform on ``IntegerField``.
|
||||
The default lookup name is ``chr``.
|
||||
|
||||
Usage example::
|
||||
Usage example:
|
||||
|
||||
.. code-block:: pycon
|
||||
|
||||
>>> from django.db.models.functions import Chr
|
||||
>>> Author.objects.create(name='Margaret Smith')
|
||||
@@ -1311,7 +1423,9 @@ This function will never have a null result. On backends where a null argument
|
||||
results in the entire expression being null, Django will ensure that each null
|
||||
part is converted to an empty string first.
|
||||
|
||||
Usage example::
|
||||
Usage example:
|
||||
|
||||
.. code-block:: pycon
|
||||
|
||||
>>> # Get the display name as "name (goes_by)"
|
||||
>>> from django.db.models import CharField, Value as V
|
||||
@@ -1333,7 +1447,9 @@ Usage example::
|
||||
|
||||
Returns the first ``length`` characters of the given text field or expression.
|
||||
|
||||
Usage example::
|
||||
Usage example:
|
||||
|
||||
.. code-block:: pycon
|
||||
|
||||
>>> from django.db.models.functions import Left
|
||||
>>> Author.objects.create(name='Margaret Smith')
|
||||
@@ -1349,7 +1465,9 @@ Usage example::
|
||||
Accepts a single text field or expression and returns the number of characters
|
||||
the value has. If the expression is null, then the length will also be null.
|
||||
|
||||
Usage example::
|
||||
Usage example:
|
||||
|
||||
.. code-block:: pycon
|
||||
|
||||
>>> # Get the length of the name and goes_by fields
|
||||
>>> from django.db.models.functions import Length
|
||||
@@ -1360,7 +1478,9 @@ Usage example::
|
||||
>>> print(author.name_length, author.goes_by_length)
|
||||
(14, None)
|
||||
|
||||
It can also be registered as a transform. For example::
|
||||
It can also be registered as a transform. For example:
|
||||
|
||||
.. code-block:: pycon
|
||||
|
||||
>>> from django.db.models import CharField
|
||||
>>> from django.db.models.functions import Length
|
||||
@@ -1378,7 +1498,9 @@ representation.
|
||||
|
||||
It can also be registered as a transform as described in :class:`Length`.
|
||||
|
||||
Usage example::
|
||||
Usage example:
|
||||
|
||||
.. code-block:: pycon
|
||||
|
||||
>>> from django.db.models.functions import Lower
|
||||
>>> Author.objects.create(name='Margaret Smith')
|
||||
@@ -1395,7 +1517,9 @@ Returns the value of the given text field or expression padded on the left side
|
||||
with ``fill_text`` so that the resulting value is ``length`` characters long.
|
||||
The default ``fill_text`` is a space.
|
||||
|
||||
Usage example::
|
||||
Usage example:
|
||||
|
||||
.. code-block:: pycon
|
||||
|
||||
>>> from django.db.models import Value
|
||||
>>> from django.db.models.functions import LPad
|
||||
@@ -1423,7 +1547,9 @@ string.
|
||||
|
||||
It can also be registered as a transform as described in :class:`Length`.
|
||||
|
||||
Usage example::
|
||||
Usage example:
|
||||
|
||||
.. code-block:: pycon
|
||||
|
||||
>>> from django.db.models.functions import MD5
|
||||
>>> Author.objects.create(name='Margaret Smith')
|
||||
@@ -1444,7 +1570,9 @@ than one character long.
|
||||
It can also be registered as a transform as described in :class:`Length`.
|
||||
The default lookup name is ``ord``.
|
||||
|
||||
Usage example::
|
||||
Usage example:
|
||||
|
||||
.. code-block:: pycon
|
||||
|
||||
>>> from django.db.models.functions import Ord
|
||||
>>> Author.objects.create(name='Margaret Smith')
|
||||
@@ -1460,7 +1588,9 @@ Usage example::
|
||||
Returns the value of the given text field or expression repeated ``number``
|
||||
times.
|
||||
|
||||
Usage example::
|
||||
Usage example:
|
||||
|
||||
.. code-block:: pycon
|
||||
|
||||
>>> from django.db.models.functions import Repeat
|
||||
>>> Author.objects.create(name='John', alias='j')
|
||||
@@ -1478,7 +1608,9 @@ Replaces all occurrences of ``text`` with ``replacement`` in ``expression``.
|
||||
The default replacement text is the empty string. The arguments to the function
|
||||
are case-sensitive.
|
||||
|
||||
Usage example::
|
||||
Usage example:
|
||||
|
||||
.. code-block:: pycon
|
||||
|
||||
>>> from django.db.models import Value
|
||||
>>> from django.db.models.functions import Replace
|
||||
@@ -1500,7 +1632,9 @@ expression in reverse order.
|
||||
It can also be registered as a transform as described in :class:`Length`. The
|
||||
default lookup name is ``reverse``.
|
||||
|
||||
Usage example::
|
||||
Usage example:
|
||||
|
||||
.. code-block:: pycon
|
||||
|
||||
>>> from django.db.models.functions import Reverse
|
||||
>>> Author.objects.create(name='Margaret Smith')
|
||||
@@ -1515,7 +1649,9 @@ Usage example::
|
||||
|
||||
Returns the last ``length`` characters of the given text field or expression.
|
||||
|
||||
Usage example::
|
||||
Usage example:
|
||||
|
||||
.. code-block:: pycon
|
||||
|
||||
>>> from django.db.models.functions import Right
|
||||
>>> Author.objects.create(name='Margaret Smith')
|
||||
@@ -1553,7 +1689,9 @@ the string.
|
||||
|
||||
They can also be registered as transforms as described in :class:`Length`.
|
||||
|
||||
Usage example::
|
||||
Usage example:
|
||||
|
||||
.. code-block:: pycon
|
||||
|
||||
>>> from django.db.models.functions import SHA1
|
||||
>>> Author.objects.create(name='Margaret Smith')
|
||||
@@ -1581,7 +1719,9 @@ Returns a positive integer corresponding to the 1-indexed position of the first
|
||||
occurrence of ``substring`` inside ``string``, or 0 if ``substring`` is not
|
||||
found.
|
||||
|
||||
Usage example::
|
||||
Usage example:
|
||||
|
||||
.. code-block:: pycon
|
||||
|
||||
>>> from django.db.models import Value as V
|
||||
>>> from django.db.models.functions import StrIndex
|
||||
@@ -1613,7 +1753,9 @@ Returns a substring of length ``length`` from the field or expression starting
|
||||
at position ``pos``. The position is 1-indexed, so the position must be greater
|
||||
than 0. If ``length`` is ``None``, then the rest of the string will be returned.
|
||||
|
||||
Usage example::
|
||||
Usage example:
|
||||
|
||||
.. code-block:: pycon
|
||||
|
||||
>>> # Set the alias to the first 5 characters of the name as lowercase
|
||||
>>> from django.db.models.functions import Lower, Substr
|
||||
@@ -1631,7 +1773,9 @@ Usage example::
|
||||
Returns the value of the given text field or expression with leading and
|
||||
trailing spaces removed.
|
||||
|
||||
Usage example::
|
||||
Usage example:
|
||||
|
||||
.. code-block:: pycon
|
||||
|
||||
>>> from django.db.models.functions import Trim
|
||||
>>> Author.objects.create(name=' John ', alias='j')
|
||||
@@ -1650,7 +1794,9 @@ representation.
|
||||
|
||||
It can also be registered as a transform as described in :class:`Length`.
|
||||
|
||||
Usage example::
|
||||
Usage example:
|
||||
|
||||
.. code-block:: pycon
|
||||
|
||||
>>> from django.db.models.functions import Upper
|
||||
>>> Author.objects.create(name='Margaret Smith')
|
||||
|
||||
Reference in New Issue
Block a user