window.median

支持的语言：

规则

window.median(numeric_values, should_ignore_zero_values)

说明

返回输入值的中位数。如果有 2 个中位数值，则只会以不确定的方式选择 1 个作为返回值。

形参数据类型

INT|FLOAT，BOOL

返回类型

FLOAT

代码示例

示例 1

此示例会在输入值不为零时返回中位数。

rule median_file_size {
    meta:
    events:
      $e.metadata.event_type = "FILE_COPY"
        $userid = $e.principal.user.userid
    match:
      $userid over 1h
    outcome:
      $median_file_size = window.median($e.principal.file.size) // returns 2 if the file sizes in the match window are [1, 2, 3]
  condition:
      $e
}

示例 2

此示例展示了当输入包含一些不应忽略的零值时，如何返回中位数。

rule median_file_size {
    meta:
    events:
      $e.metadata.event_type = "FILE_COPY"
        $userid = $e.principal.user.userid
    match:
      $userid over 1h
    outcome:
      $median_file_size = window.median($e.principal.file.size) // returns 1 if the file sizes in the match window are [0,0, 1, 2, 3]
  condition:
      $e
}

示例 3

此示例返回中位数，前提是输入包含一些应忽略的零值。

rule median_file_size {
    meta:
    events:
      $e.metadata.event_type = "FILE_COPY"
        $userid = $e.principal.user.userid
    match:
      $userid over 1h
    outcome:
      $median_file_size = window.median($e.principal.file.size, true) // returns 2 if the file sizes in the match window are [0,0, 1, 2, 3]
  condition:
      $e
}

示例 4

此示例返回输入包含应忽略的所有零值时的中位数。

rule median_file_size {
    meta:
    events:
      $e.metadata.event_type = "FILE_COPY"
        $userid = $e.principal.user.userid
    match:
      $userid over 1h
    outcome:
      $median_file_size = window.median($e.principal.file.size) // returns 0 if the file sizes in the match window are [0,0]
  condition:
      $e
}

示例 5

此示例表明，当存在多个中位数时，系统只会返回一个中位数。

rule median_file_size {
    meta:
    events:
      $e.metadata.event_type = "FILE_COPY"
        $userid = $e.principal.user.userid
    match:
      $userid over 1h
    outcome:
      $median_file_size = window.median($e.principal.file.size) // returns 1 if the file sizes in the match window are [1, 2, 3, 4]
  condition:
      $e
}