How do I keep the compute block in PROC REPORT from using scientific notation?

[Syntas_error]

My "period" variable is a character variable which has the format $32. It can take on the following values:

2004-2007

[...]

2013-2016

2015-2016,2018

2018, 2020

2018,2020,2021

2020,2021,2022

I use the compute block in PROC REPORT in order to use these periods as headlines for the values in that time period:

ods excel file="[path]";
ods excel options(sheet_interval='bygroup' sheet_name="#byval(bladnamn)");


PROC REPORT data=export;
by bladnamn;
column period variabelnamn bladnamn variabel_cat_varde (kon,(andel CI_lower CI_upper lillan));
/* define variabelnamn / order order=internal;*/
define period / group order=internal descending format=$32. noprint;
define variabelnamn / group order=data noprint;
define order / order order=internal noprint;
define variabel / order order=internal noprint;
define bladnamn / group order=data noprint;
define variabel_cat_varde / order=data group;
/*define alder_grupp / order=data group;*/
define andel / mean;
define CI_lower / mean;
define CI_upper / mean;
define lillan / mean;
DEFINE kon / ACROSS ORDER=INTERNAL; 

compute before period /style={just=left};;
period_char= put(period, $32.);
line period_char $char200.;
endcomp;

compute before variabelnamn /style={just=left};;
line variabelnamn $char200.;
endcomp;

run;

ods excel close;

The "period" values separated by commas are however converted to scientific notation in the COMPUTE block, despite my best efforts:

This is however just an issue with the comma-separated values.  More specifically, this only seems to happen with the entries with three comma-separated values.

Can I keep this from happening and in that case how?

[Ksharp · Accepted solution]

data have;
input period :$40. a $ x;
cards;
2018,2020,2021 a1 12
2018,2020,2021 a2 1
2020,2021,2022 b1  6
2020,2021,2022 b2 7
;

ods excel file='c:\temp\temp.xlsx';
proc report data=have nowd;
column period a x;
define period/group noprint;
define a/display;
define x/display;
 
compute before period /style={just=left tagattr='type:string'};
line period $char200.;
endcomp;

run;
ods excel close;

[Syntas_error]

That works, thanks!