$pow (aggregation)
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Definition
-
$pow
-
New in version 3.2.
Raises a number to the specified exponent and returns the result.
$pow
has the following syntax:The
<number>
expression can be any valid expression as long as it resolves to a number.The
<exponent>
expression can be any valid expression as long as it resolves to a number.You cannot raise
0
to a negative exponent.
Behavior
The result will have the same type as the input except when it cannot be represented accurately in that type. In these cases:
- A 32-bit integer will be converted to a 64-bit integer if the result is representable as a 64-bit integer.
- A 32-bit integer will be converted to a double if the result is not representable as a 64-bit integer.
- A 64-bit integer will be converted to double if the result is not representable as a 64-bit integer.
If either argument resolves to a value of null
or refers to a field that is missing, $pow
returns null
. If either argument resolves to NaN
, $pow
returns NaN
.
Example | Results |
---|---|
{ $pow: [ 5, 0 ] } |
1 |
{ $pow: [ 5, 2 ] } |
25 |
{ $pow: [ 5, -2 ] } |
0.04 |
{ $pow: [ -5, 0.5 ] } |
NaN |