是否有矢量化并行max()和min()？

Question

我有一个data.frame列"a"和"b".我想添加名为"high"和"low"的列,其中包含a和b列中的最高和最低.

有没有办法在没有循环数据框中的行的情况下执行此操作？

编辑:这是针对OHLC数据的,因此高和低列应包含同一行上a和b之间的最高和最低元素,而不是整列.对不起,如果措辞不好.

Answer 1

听起来像你正在寻找pmax和pmin("平行"最大/分钟):

Extremes                 package:base                  R Documentation

Maxima and Minima

Description:

     Returns the (parallel) maxima and minima of the input values.

Usage:

     max(..., na.rm = FALSE)
     min(..., na.rm = FALSE)

     pmax(..., na.rm = FALSE)
     pmin(..., na.rm = FALSE)

     pmax.int(..., na.rm = FALSE)
     pmin.int(..., na.rm = FALSE)

Arguments:

     ...: numeric or character arguments (see Note).

   na.rm: a logical indicating whether missing values should be
          removed.

Details:

     ‘pmax’ and ‘pmin’ take one or more vectors (or matrices) as
     arguments and return a single vector giving the ‘parallel’ maxima
     (or minima) of the vectors.  The first element of the result is
     the maximum (minimum) of the first elements of all the arguments,
     the second element of the result is the maximum (minimum) of the
     second elements of all the arguments and so on.  Shorter inputs
     are recycled if necessary.  ‘attributes’ (such as ‘names’ or
     ‘dim’) are transferred from the first argument (if applicable).