Hiroyuki Kawakatsu wrote:
am i the only one who finds the following "feature" of the stata if
syntax parser worrying? (i observed a student doing this and was
expecting stata to correct him...):
[code redacted and run below]
--------------------------------------------------------------------------------
Stata is behaving predictably, logically and correctly.
2 < t is either true (1) or false (0). Either way, the result of the
logical test is always less than 5.
2 < t is either true (1) or false (0). Either way, the result of the
logical test is never greater than 5.
2 == 5 is either true (1) or false (0). Either way, the result of the
logical test is never equal to 5.
Joseph Coveney
.
. set obs 10
obs was 0, now 10
. gen x = 1
. gen t = _n
.
. sum x if 2<t<5 /*what do you expect?*/
Variable | Obs Mean Std. Dev. Min Max
-------------+--------------------------------------------------------
x | 10 1 0 1 1
.
. /*further experiments*/
. sum x if 2<t>5 /*?*/
Variable | Obs Mean Std. Dev. Min Max
-------------+--------------------------------------------------------
x | 0
. sum x if 2==t==5 /*correct?*/
Variable | Obs Mean Std. Dev. Min Max
-------------+--------------------------------------------------------
x | 0
. sum x if 2|t|5 /*ok*/
Variable | Obs Mean Std. Dev. Min Max
-------------+--------------------------------------------------------
x | 10 1 0 1 1
.
. /*end sample code*/
*
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