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# BITCOUNT

> Count the number of set bits.

The `BITCOUNT` command in Redis is used to count the number of set bits (bits with a value of 1) in a range of bytes within a key that is stored as a binary string. It is primarily used for bit-level operations on binary data stored in Redis.

## Arguments

<ParamField body="key" type="str" required>
  The key to get.
</ParamField>

<ParamField body="start" type="int">
  Specify the range of bytes within the binary string to count the set bits. If not provided, it counts set bits in the entire string.

  Either specify both `start` and `end` or neither.
</ParamField>

<ParamField body="end" type="int">
Specify the range of bytes within the binary string to count the set bits. If not provided, it counts set bits in the entire string.

 Either specify both `start` and `end` or neither.
</ParamField>
## Response

<ResponseField type="int" required>
  The number of set bits in the specified range.
</ResponseField>

<RequestExample>
```py Example
redis.setbit("mykey", 7, 1)
redis.setbit("mykey", 8, 1)
redis.setbit("mykey", 9, 1)

# With range
assert redis.bitcount("mykey", 0, 10) == 3

# Without range
assert redis.bitcount("mykey") == 3
```
</RequestExample>