$radiansToDegrees (aggregation)
Definition
New in version 4.2.
Converts an input value measured in radians to degrees.
$radiansToDegrees
has the following syntax:
- { $radiansToDegrees: <expression> }
$radiansToDegrees
takes any valid expression that resolves to a number.
By default $radiansToDegrees
returns values as adouble
. $radiansToDegrees
can also return valuesas a 128-bit decimal as long as the<expression>
resolves to a 128-bit decimal value.
For more information on expressions, seeExpressions.
Behavior
null, NaN, and +/- Infinity
If the argument resolves to a value of null
or refers to a fieldthat is missing, $radiansToDegrees
returns null
. Ifthe argument resolves to NaN
, $radiansToDegrees
returns NaN
. If the argument resolves to negative or positiveinfinity, $radiansToDegrees
negative or positive infinityrespectively.
Example | Results |
---|---|
{ $radiansToDegrees: NaN } | NaN |
{ $radiansToDegrees: null } | null |
{ $radiansToDegrees : Infinity} | Infinity |
{ $radiansToDegrees : -Infinity } | -Infinity |
Example
The trigonometry
collection contains a document that containsthree angles measured in radians:
- {
- "angle_a" : NumberDecimal("0.9272952180016122324285124629224290"),
- "angle_b" : NumberDecimal("0.6435011087932843868028092287173227"),
- "angle_c" : NumberDecimal("1.570796326794896619231321691639752")
- }
The following aggregation operation uses the$radiansToDegrees
expression to convert each value toits degree equivalent and add them to the input document using the$addFields
pipeline stage.
- db.trigangles.aggregate([
- {
- $addFields: {
- "angle_a_deg" : { $radiansToDegrees : "$angle_a"},
- "angle_b_deg" : { $radiansToDegrees : "$angle_b"},
- "angle_c_deg" : { $radiansToDegrees : "$angle_c"}
- }
- }
- ])
The operation returns the following document:
- {
- "_id" : ObjectId("5c50aec71c75c59232b3ede4"),
- "angle_a" : NumberDecimal("0.9272952180016122324285124629224290"),
- "angle_b" : NumberDecimal("0.6435011087932843868028092287173227"),
- "angle_c" : NumberDecimal("1.570796326794896619231321691639752"),
- "angle_a_deg" : NumberDecimal("53.13010235415597870314438744090659"),
- "angle_b_deg" : NumberDecimal("36.86989764584402129685561255909341"),
- "angle_c_deg" : NumberDecimal("90.00000000000000000000000000000000")
- }
Since angle_a
, angle_b
, and angle_c
are stored as128-bit decimals, the output of$radiansToDegrees
is a 128-bit decimal.