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$bit
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Definition
$bitThe
$bitoperator performs a bitwise update of a field. The operator supports bitwiseand, bitwiseor, and bitwisexor(i.e. exclusive or) operations. To specify a$bitoperator expression, use the following prototype:{ $bit: { <field>: { <and|or|xor>: <int> } } } Only use this operator with integer fields (either 32-bit integer or 64-bit integer).
To specify a
<field>in an embedded document or in an array, use dot notation.Note
All numbers in the
mongoshell are doubles, not integers. Use theNumberInt()or theNumberLong()constructor to specify integers. See NumberInt or NumberLong for more information.
Behavior
In MongoDB 4.4 and earlier, update operators process document fields in lexicographic order. See Update Operators Behavior for details.
Examples
Bitwise AND
Consider the following document inserted into the collection
switches:
{ _id: 1, expdata: NumberInt(13) }
The following update() operation updates the
expdata field to the result of a bitwise and operation between
the current value NumberInt(13) (i.e. 1101) and
NumberInt(10) (i.e. 1010):
db.switches.update( { _id: 1 }, { $bit: { expdata: { and: NumberInt(10) } } } )
The bitwise and operation results in the integer 8 (i.e. 1000):
1101 1010 ---- 1000
And the updated document has the following value for expdata:
{ "_id" : 1, "expdata" : 8 }
The mongo shell displays NumberInt(8) as 8.
Bitwise OR
Consider the following document inserted into the collection
switches:
{ _id: 2, expdata: NumberLong(3) }
The following update() operation updates the
expdata field to the result of a bitwise or operation between
the current value NumberLong(3) (i.e. 0011) and
NumberInt(5) (i.e. 0101):
db.switches.update( { _id: 2 }, { $bit: { expdata: { or: NumberInt(5) } } } )
The bitwise or operation results in the integer 7 (i.e. 0111):
0011 0101 ---- 0111
And the updated document has the following value for expdata:
{ "_id" : 2, "expdata" : NumberLong(7) }
Bitwise XOR
Consider the following document in the collection switches:
{ _id: 3, expdata: NumberLong(1) }
The following update() operation updates the
expdata field to the result of a bitwise xor operation between
the current value NumberLong(1) (i.e. 0001) and
NumberInt(5) (i.e. 0101):
db.switches.update( { _id: 3 }, { $bit: { expdata: { xor: NumberInt(5) } } } )
The bitwise xor operation results in the integer 4:
0001 0101 ---- 0100
And the updated document has the following value for expdata:
{ "_id" : 3, "expdata" : NumberLong(4) }