Redis BITCOUNT 行为
Redis BITCOUNT behavior
redis bitcount 命令如何工作？
setbit test 1 1
setbit test 3 1
计数位。
bitcount test
returns 2
范围计数。
bitcount test 1 2
returns 0
为什么？我想我应该为 1 和 2 之间的位位置取 1，我们只设置了一位。
start 和 end 参数指的是 字节 。所以你要问字符串的第二个和第三个字节中的位数。您只在第一个字节中设置了位，所以答案是 0.
不幸的是 BITCOUNT doesn't explain that, but it is mentioned in the documentation for BITPOS 的文档：
It is possible to look for bits only in a specified interval passing the additional arguments start and end.... The range is interpreted as a range of bytes and not a range of bits, so start=0 and end=2 means to look at the first three bytes.
redis bitcount 命令如何工作？
setbit test 1 1
setbit test 3 1
计数位。
bitcount test
returns 2
范围计数。
bitcount test 1 2
returns 0
为什么？我想我应该为 1 和 2 之间的位位置取 1，我们只设置了一位。
start 和 end 参数指的是 字节 。所以你要问字符串的第二个和第三个字节中的位数。您只在第一个字节中设置了位，所以答案是 0.
不幸的是 BITCOUNT doesn't explain that, but it is mentioned in the documentation for BITPOS 的文档：
It is possible to look for bits only in a specified interval passing the additional arguments start and end.... The range is interpreted as a range of bytes and not a range of bits, so
start=0andend=2means to look at the first three bytes.