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$bit![](/docs/v5.3/assets/link.svg)
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Definition![](/docs/v5.3/assets/link.svg)
$bit
The
$bit
operator performs a bitwise update of a field. The operator supports bitwiseand
, bitwiseor
, and bitwisexor
(i.e. exclusive or) operations. To specify a$bit
operator 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
mongosh
are doubles, not integers. Use theNumberInt()
or theNumberLong()
constructor to specify integers. See NumberInt or NumberLong for more information.
Behavior![](/docs/v5.3/assets/link.svg)
Starting in MongoDB 5.0, mongod
no longer raises an
error when you use an update operator like $bit
with an empty operand expression ( { }
). An empty update results
in no changes and no oplog entry is created (meaning that the
operation is a no-op).
Starting in MongoDB 5.0, update operators process document fields with string-based names in lexicographic order. Fields with numeric names are processed in numeric order. See Update Operators Behavior for details.
Examples![](/docs/v5.3/assets/link.svg)
The following examples use the switches
collection:
db.switches.insertMany( [ { _id: 1, expdata: Int32(13) }, { _id: 2, expdata: Int32(3) }, { _id: 3, expdata: Int32(1) } ] )
Bitwise AND![](/docs/v5.3/assets/link.svg)
Use a bitwise and
in the updateOne()
operation to update expdata
.
db.switches.updateOne( { _id: 1 }, { $bit: { expdata: { and: Int32( 10 ) } } } )
The bitwise and
operation:
gets the bitwise value of
expdata
uses
and
to apply the bitwise value of Int32(10)updates
expdata
with the result, 1000
1101 // expdata 1010 // Int32(10) ---- 1000
Binary 1000 is equivalent to Int32(8). The
db.switches.find( { _id: 1 } )
command returns the following
document:
{ "_id" : 1, "expdata" : 8 }
Bitwise OR![](/docs/v5.3/assets/link.svg)
Use a bitwise or
in the updateOne()
operation to update expdata
.
db.switches.updateOne( { _id: 2 }, { $bit: { expdata: { or: Int32( 5 ) } } } )
The bitwise or
operation:
gets the bitwise value of
expdata
uses
or
to apply the bitwise value of Int32(5)updates
expdata
with the result, 0111
0111 // expdata 0101 // Int32(5) ---- 0111
Binary 0111 is equivalent to Int32(7). The
db.switches.find( { _id: 2 } )
command returns the following
document:
{ "_id" : 2, "expdata" : 7 }
Bitwise XOR![](/docs/v5.3/assets/link.svg)
Use a bitwise xor
in the updateOne()
operation to update expdata
.
db.switches.updateOne( { _id: 3 }, { $bit: { expdata: { xor: Int32( 5 ) } } } )
The bitwise and
operation:
gets the bitwise value of
expdata
uses
and
to apply the bitwise value of Int32(5)updates
expdata
with the result, 0100
0001 // expdata 0101 // Int32(5) ---- 0100
Binary 0100 is equivalent to Int32(4)
. The
db.switches.find( { _id: 3 } )
command returns the following
document:
{ "_id" : 1, "expdata" : 4 }