periods               package:timeDate               R Documentation

_R_o_l_l_i_n_g _p_e_r_i_o_d_s

_D_e_s_c_r_i_p_t_i_o_n:

     Returns start and end dates for a rolling periods

_U_s_a_g_e:

     periods(x, period = "12m", by = "1m", offset = "0d")
     periodicallyRolling(x, period = "52w", by = "4w", offset = "0d")
     monthlyRolling(x, period = "12m", by = "1m")

_A_r_g_u_m_e_n_t_s:

       x: an object of class timeDate

  period: a span string, consisting of a length integer and a unit
          value, e.g. "52w" for 52 weeks.

      by: a span string, consisting of a length integer and a unit
          value, e.g. "4w" for 4 weeks.

  offset: a span string, consisting of a length integer and a unit
          value, e.g. "0d" for no offset.

_D_e_t_a_i_l_s:

     Periodically Rolling - Allowed unit values are "m" for 4 weeks,
     "w" for weeks, "d" for days, "H" for hours, "M" for minutes, and
     "S" for seconds.

     Monthly Calendar Rolling - The only allowed allowed unit value is
     "m" for monthly periods. Express a quarterly period by "3m", a
     semester by "6m", a year by "12m" etc.

_E_x_a_m_p_l_e_s:

     x <- timeSequence(from = "2001-01-01", to = "2009-01-01", by = "day") 

     periods(x, "12m", "1m")
     periods(x, "52w", "4w")
         
     periodicallyRolling(x)
         
     monthlyRolling(x)

