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Sort by a user specified scoring expression.
Inherits From: expected_type
google.appengine.api.search.SortExpression(
expression, direction=DESCENDING, default_value=None
)
For example, the following will sort documents on a numeric field named 'length' in ascending order, assigning a default value of sys.maxint for documents which do not specify a 'length' field.
SortExpression(expression='length', direction=sort.SortExpression.ASCENDING, default_value=sys.maxint)
The following example will sort documents on a date field named 'published_date' in descending order, assigning a default value of 1999-12-31 for documents which do not specify a 'published_date' field.
SortExpression(expression='published_date', default_value=datetime.date(year=1999, month=12, day=31))
The following example will sort documents on a text field named 'subject' in descending order, assigning a default value of '' for documents which do not specify a 'subject' field.
SortExpression(expression='subject')
Args | |
|---|---|
expression
|
An expression to be evaluated on each matching document to sort by. The expression must evaluate to a text or numeric value. The expression can simply be a field name, or some compound expression such as "_score + count(likes) * 0.1" which will add the score from a scorer to a count of the values of a likes field times 0.1. See https://developers.google.com/appengine/docs/python/search/overview#Expressions for a list of legal expressions. |
direction
|
The direction to sort the search results, either ASCENDING or DESCENDING |
default_value
|
The default value of the expression. The default_value is returned if expression cannot be calculated, for example, if the expression is a field name and no value for that named field exists. A text value must be specified for text sorts. A numeric value must be specified for numeric sorts. A date value must be specified for date sorts. |
Raises | |
|---|---|
TypeError
|
If any of the parameters has an invalid type, or an unknown attribute is passed. |
ValueError
|
If any of the parameters has an invalid value. |
ExpressionError
|
If the expression string is not parseable. |
Attributes | |
|---|---|
default_value
|
Returns a default value for the expression if no value computed. |
direction
|
Returns the direction to sort expression: ASCENDING or DESCENDING. |
expression
|
Returns the expression to sort by. |