help sort dialog: sort
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Title
[D] sort -- Sort data
Syntax
sort varlist [in] [, stable]
Menu
Data > Sort > Ascending sort
Description
sort arranges the observations of the current data into ascending order
based on the values of the variables in varlist. There is no limit to
the number of variables in the varlist. Missing numeric values (see
missing) are interpreted as being larger than any other number, so they
are placed last with . < .a < .b < ... < .z. When you sort on a string
variable, however, null strings are placed first. The dataset is marked
as being sorted by varlist unless in range is specified. If in range is
specified, only those observations are rearranged. The unspecified
observations remain in the same place.
Option
stable specifies that observations with the same values of the variables
in varlist keep the same relative order in the sorted data that they
had previously. For instance, consider the following data:
x b
3 1
1 2
1 1
1 3
2 4
Typing sort x without the stable option produces one of the following
6 orderings.
x b | x b | x b | x b | x b | x b
1 2 | 1 2 | 1 1 | 1 1 | 1 3 | 1 3
1 1 | 1 3 | 1 3 | 1 2 | 1 1 | 1 2
1 3 | 1 1 | 1 2 | 1 3 | 1 2 | 1 1
2 4 | 2 4 | 2 4 | 2 4 | 2 4 | 2 4
3 1 | 3 1 | 3 1 | 3 1 | 3 1 | 3 1
Without the stable option, the ordering of observations with equal
values of varlist is randomized. With sort x, stable, you will
always get the first ordering and never the other five.
If your intent is to have the observations sorted first on x and then
on b within tied values of x (the fourth ordering above), you should
type sort x b rather than sort x, stable.
stable is seldom used, and, when specified, causes sort to execute
more slowly.
Examples
Setup
. sysuse auto
. keep make mpg weight
Arrange observations into ascending order based on the values of mpg
. sort mpg
Same as above, but for observations with the same values of mpg, keep
them in the same relative order in the sorted data as they had previously
. sort mpg, stable
List the 5 cars with the lowest mpg
. list make mpg in 1/5
List the 5 cars with the highest mpg
. list make mpg in -5/L
Arrange observations into ascending order based on the values of mpg, and
within each mpg category arrange observations into ascending order based
on the values of weight
. sort mpg weight
List the 8 cars with the lowest mpg, and within each mpg category with
the lowest weight
. list in 1/8
Also see
Manual: [D] sort
Help: [D] describe, [D] gsort
