Skip to content
HotKVDocs

Ask the HotKV docs

Answers come only from these docs and can be wrong; check the linked pages before you rely on them.

BITCOUNT

Last updated 
BITCOUNT key [start end [BYTE | BIT]]
Group
Bitmap
Complexity
O(N) where N is the size of the range
Arity
-2 (at least 2 words, counting the command name)
Flags
read-only
Keys
first 1, last 1, step 1
HotKV Cloud
All plans
On-Premise
no license needed

BITCOUNT counts the bits set to 1 in the string at key. Without a range it counts the whole string. With start and end it counts only that range, both ends included; negative values count back from the end of the string. By default the range is in bytes; add BIT to give it in bits. A missing key counts as 0.

Options

Section titled “Options”
Option Effect
start end Count only this range. Both must be given together.
BYTE start and end are byte offsets (the default).
BIT start and end are bit offsets.

Return value

Section titled “Return value”
Case RESP2 RESP3
Always Integer: the number of set bits Integer

Errors:

  • ERR syntax error for a start without an end, or a unit other than BYTE or BIT.
  • ERR value is not an integer or out of range when start or end is not an integer.
  • WRONGTYPE when the key holds a value that is not a string.

Examples

Section titled “Examples”
127.0.0.1:6379> SET mask "hi"
OK
127.0.0.1:6379> BITCOUNT mask
(integer) 7
127.0.0.1:6379> BITCOUNT mask 0 0
(integer) 3
127.0.0.1:6379> BITCOUNT mask 5 10 BIT
(integer) 2

Compatibility

Section titled “Compatibility”

Same as Redis 7 and Valkey 8.

See also

Section titled “See also”

BITPOS, SETBIT, BITOP