正如@MrFlick 已经指出的那样，您没有绕过子集的基本逻辑.让您更轻松地对特定 data.frame 进行子集化的一种方法是定义一个函数，该函数在您的示例中接受两个输入，例如 DATE1 和 DATE2，然后返回IBOV_RET 根据这些子集参数的子集.

As already pointed out by @MrFlick, you dont get around the basic logic of subsetting. One way to make it easier for you to subset your specific data.frame would be to define a function that takes two inputs like DATE1 and DATE2 in your example and then returns the subset of IBOV_RET according to those subset parameters.

myfunc <- function(x,y){IBOV_RET[IBOV_RET$DATE >= x & IBOV_RET$DATE <= y,]}

DATE1 <- as.Date("1993-04-29")
DATE2 <- as.Date("1993-05-04")

Test <- myfunc(DATE1,DATE2)    

#> Test
#        DATE  X1D_RETURN
#2 1993-04-29 -0.02469136
#3 1993-04-30  0.01687764
#4 1993-05-03  0.00000000
#5 1993-05-04  0.03319502

您也可以直接在myfunc中输入具体日期:

You can also enter the specific dates directly into myfunc:

myfunc(as.Date("1993-04-29"),as.Date("1993-05-04")) #will produce the same result