/* a snippet that will count the number of
occurences of characters in strings
including the generation of lower case letters
for demonstration
SSA 10/11/02
*/
/* we're just going to look for the first five
letters
*/
#delimit ;
set obs 100;
gen str10 avar = "";
for num 1/10:replace avar = avar + char(int(uniform() * 6 + 97)) if X >
0 ;
/* so now we have strings of the first 5 letters
the line below counts them
note if the strings are exactly the same length
it is unnecessary to test length
*/
/* for clarity output vars are initialized in a
separate line
*/
for LETTER in any a b c d e:gen int LETTERcount = 0 ;
for LETTER in any a b c d e:
for COLUMN in num 1/10:
replace LETTERcount = LETTERcount + 1
if substr(avar,COLUMN,1) == "LETTER" &
COLUMN <= length(avar)
;
/* all done, look at the results */
for var *count:tab X;
/* This kind of thing can be reversed as well if you
need to concatenate variables
*/
/***********************************
Sidney Atwood
Manager
Instructional Computing Facility
Harvard School of Public Health
Kresge, LL-17
677 Huntington Avenue
Boston, MA 02115
617-432-3134
617-432-4998 - Fax
************************************/
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