Nick/Gary,
Thanks very much for your help. -asciiplot- provides a particularly useful
display of the sort 'order' of characters.
Cheers!
Steve
-----Original Message-----
From: [email protected]
[mailto:[email protected]] On Behalf Of Nick Cox
Sent: 13 May 2009 18:14
To: [email protected]
Subject: st: RE: RE: RE: Strings and the greater than/less than operators
I wrote -char()-, not -char-. The () signal a function, -char()-. For
example,
. di char(65)
A
. di char(97)
a
Referring to -char()- is more precise than referring to (say) ASCII order,
which doesn't mean the same thing in absolutely all circumstances.
Stata doesn't offer an inverse to -char()-, but -asciiplot- from SSC gives
you a graphical display of the characters on your system. In any case,
typing e.g.
di ("a" > "A")
gives you 1 for true and 0 for false.
Incidentally, these data look like first parts of UK postcodes. Right or
wrong, you might use -trim()- to lose the trailing spaces now in order not
to be bitten again.
Nick
[email protected]
sdm1
Noooooooooooo!
Thanks Nick...and, of course, you're dead right.
The giveaway, I realise now, is the alignment of the values of code under
the heading 'code' in the tabulation. I think that the last character
aligns vertically with the 'e' of 'code'.
The only bit I don't understand is: "The order is that of -char()-".
It sounds to me as if char is user defined. This is from the help for
char:
The dataset itself and each variable within the dataset have associated
with them a set of characteristics.
Characteristics are named and referred to as varname[charname], where
varname is the name of a variable or _dta.
The characteristics contain text. Characteristics are stored with the
dataset in the Stata-format .dta dataset,
so they are recalled whenever the dataset is loaded.
If characteristics for a variable are not defined by the user, what's the
default order? Is there a list somewhere which will tell me the order in
which Stata sorts characters e.g. alphabetric, numeric, spaces, etc. Or am
I misinterpreting here?
Once again, thanks for your help.
Nick Cox
General question: Absolutely. The order is that of -char()-.
Specific question: "N05 " > "N05". You have trailing spaces. They are
characters too.
Nick
[email protected]
Steve
Can the greater than (>) and less than (<) operators be applied to strings?
If the answer is 'yes' (as I thought), why is "N05" included in the output
for the following command?
. tab code admimeth if (admimeth==31 | admimeth==32) & (code>"N05" &
code<"N13")
| admimeth
code | 31 32 | Total
-----------+----------------------+----------
N05 | 103 163 | 266
N06 | 23,858 132 | 23,990
N07 | 364,687 2,653 | 367,340
N08 | 8,079 18 | 8,097
N09 | 70,953 132 | 71,085
N10 | 24,606 88 | 24,694
N11 | 123,635 256 | 123,891
N12 | 546,148 21,998 | 568,146
-----------+----------------------+----------
Total | 1,162,069 25,440 | 1,187,509
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