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$atan2 (aggregation)

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$atan2

New in version 4.2.

Returns the inverse tangent (arc tangent) of y / x, where y and x are the first and second values passed to the expression respectively.

$atan2 has the following syntax:

{ $atan2: [ <expression 1>, <expression 2> ] }

$atan2 takes any valid expression that resolves to a number.

$atan2 returns values in radians. Use $radiansToDegrees operator to convert the output value from radians to degrees.

By default $atan2 returns values as a double. $atan2 can also return values as a 128-bit decimal as long as the <expression> resolves to a 128-bit decimal value.

For more information on expressions, see Expressions.

If the first argument to $atan2 is null, $atan2 returns null. If the first argument to $atan2 is NaN, $atan2 returns NaN. If the first argument resolves to a number and the second argument resolves to either NaN or null, $atan2 returns the NaN or null respectively.

Example
Results

{ $atan2: [ NaN, <value> ] }

or

{ $atan2: [ <value>, NaN ] }

NaN

{ $atan2: [ null, <value> ] }

or

{ $atan2: [ <value>, null ] }

null

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