Ops.Date package:base R Documentation _O_p_e_r_a_t_o_r_s _o_n _t_h_e _D_a_t_e _C_l_a_s_s _D_e_s_c_r_i_p_t_i_o_n: Operators for the '"Date"' class. There is an 'Ops' method and specific methods for '+' and '-' for the 'Date' class. _U_s_a_g_e: date + x date - x date1 lop date2 _A_r_g_u_m_e_n_t_s: date: date objects date1, date2: date objects or character vectors. (Character vectors are converted by 'as.Date'.) x: a numeric vector (in days) _or_ an object of class '"difftime"'. lop: One of '==', '!=', '<', '<=', '>' or '>='. _E_x_a_m_p_l_e_s: (z <- Sys.Date()) z + 10 z < c("2006-06-01", "2007-01-01", "2010-01-01")