Replicate recode results using floor, int or ceil function

[Rodrigo Badilla]

Hi all,

I am trying to replicate recode results using floor, int or ceil function, my focus is recode a big data base with age variable, for this reason I would like use this function, lamentably i get differents results in frequency, example:

clear all
set more off
sysuse auto

#delimit ;
 recode mpg
(12/16= 1 12-16)
(17/21= 2 17-21)
(22/26= 3 22-26)
(27/31= 4 27-31)
(32/36= 5 32-36)
(37/41= 6 37-41)
(42/max= 7 34-max), gen(recodempg)
 ;
 #delimit cr

 tab recodempg


  RECODE of |
        mpg |
   (Mileage |
     (mpg)) |      Freq.     Percent        Cum.
------------+-----------------------------------
      12-16 |         14       18.92       18.92
      17-21 |         29       39.19       58.11
      22-26 |         20       27.03       85.14
      27-31 |          7        9.46       94.59
      32-36 |          3        4.05       98.65
      37-41 |          1        1.35      100.00
------------+-----------------------------------
      Total |         74      100.00



gen flormpg =4 * floor(mpg/4)
tab flormpg


    flormpg |      Freq.     Percent        Cum.
------------+-----------------------------------
         12 |         10       13.51       13.51
         16 |         25       33.78       47.30
         20 |         16       21.62       68.92
         24 |         12       16.22       85.14
         28 |          7        9.46       94.59
         32 |          3        4.05       98.65
         40 |          1        1.35      100.00
------------+-----------------------------------
      Total |         74      100.00



gen intempg =4 * int(mpg/4)
tab intempg


    intempg |      Freq.     Percent        Cum.
------------+-----------------------------------
         12 |         10       13.51       13.51
         16 |         25       33.78       47.30
         20 |         16       21.62       68.92
         24 |         12       16.22       85.14
         28 |          7        9.46       94.59
         32 |          3        4.05       98.65
         40 |          1        1.35      100.00
------------+-----------------------------------
      Total |         74      100.00



gen ceilmpg =4 * ceil(mpg/4)
tab ceilmpg


    ceilmpg |      Freq.     Percent        Cum.
------------+-----------------------------------
         12 |          2        2.70        2.70
         16 |         12       16.22       18.92
         20 |         24       32.43       51.35
         24 |         17       22.97       74.32
         28 |         11       14.86       89.19
         32 |          4        5.41       94.59
         36 |          3        4.05       98.65
         44 |          1        1.35      100.00
------------+-----------------------------------
      Total |         74      100.00

[William Lisowski]

These all produce the same results as your recode command.

gen flormpg = 12 + 5 * floor((mpg-12)/5)
tab flormpg

gen intempg = 12 + 5 * int((mpg-12)/5)
tab intempg

gen ceilmpg =  7 + 5 * ceil((mpg-11)/5)
tab ceilmpg

[Rodrigo Badilla]

Thanks William Lisowski your code works fine!.

Regards

[Scott Merryman]

. sysuse auto,clear
(1978 Automobile Data)

. 
. #delimit ;
delimiter now ;
.  recode mpg
> (12/16= 1 12-16)
> (17/21= 2 17-21)
> (22/26= 3 22-26)
> (27/31= 4 27-31)
> (32/36= 5 32-36)
> (37/41= 6 37-41)
> (42/max= 7 34-max), gen(recodempg)
>  ;
(74 differences between mpg and recodempg)

.  #delimit cr
delimiter now cr
. 
. tab recodempg

  RECODE of |
        mpg |
   (Mileage |
     (mpg)) |      Freq.     Percent        Cum.
------------+-----------------------------------
      12-16 |         14       18.92       18.92
      17-21 |         29       39.19       58.11
      22-26 |         20       27.03       85.14
      27-31 |          7        9.46       94.59
      32-36 |          3        4.05       98.65
      37-41 |          1        1.35      100.00
------------+-----------------------------------
      Total |         74      100.00

. gen recodempg2 = 5*(ceil(mpg/5.3333333333333333)-2)+11

. tab recodempg2

 recodempg2 |      Freq.     Percent        Cum.
------------+-----------------------------------
         16 |         14       18.92       18.92
         21 |         29       39.19       58.11
         26 |         20       27.03       85.14
         31 |          7        9.46       94.59
         36 |          3        4.05       98.65
         41 |          1        1.35      100.00
------------+-----------------------------------
      Total |         74      100.00

.

[Rodrigo Badilla]

Thanks Scott for you reply.
Regards