how to create comma separated value in progress openEdge - progress-4gl

Question

newbie question here.
I need to create a list. but my problem is what is the best way to not start with a comma?
eg:
output to /usr2/appsrv/test/Test.txt.
def var dTextList as char.
for each emp no-lock:
dTextList = dTextList + ", " + emp.Name.
end.
put unformatted dTextList skip.
output close.
then my end result is
, jack, joe, brad
what is the best way to get rid of the leading comma?
thank you

Answer 1

Here's one way:
ASSIGN
dTextList = dTextList + ", " WHEN dTextList > ""
dTextList = dTextList + emp.Name
.

Answer 2

This does it without any conditional logic:
for each emp no-lock:
csv = csv + emp.Name + ",".
end.
right-trim( csv, "," ).
or you can do this:
for each emp no-lock:
csv = substitute( "&1,&2" csv, emp.Name ).
end.
trim( csv, "," ).
Which also has the advantage of playing nicely with unknown values (the ? value...)
TRIM() trims both sides, LEFT-TRIM() only does leading characters and RIGHT-TRIM() gets trailing characters.

Answer 3

My vanilla list:
output to /usr2/appsrv/test/Test.txt.
def var dTextList as char no-undo.
for each emp no-lock:
dTextList = substitute( "&1, &2", dTextList, emp.Name )
end.
put unformatted substring( dTextList, 3 ) skip.
output close.
substitute prevents unknowns from wiping out list
keep list delimiter checking outside of loop
generally leave the list delimiter prefixed unless the prefix really needs to go as in the case when outputting it
When using delimited lists often you may want to consider a creating a list class to remove this irrelevant noise out of your code so that you can functionally just add an item to a list and export a list without tinkering with these details every time.

Answer 4

I usually do
ASSIGN dTextList = dTextList + (if dTextList = '' then '' else ',') + emp.name.

Answer 5

I come up (well my colleague did) he come up with this:
dTextList = substitute ("&1&3&2", dTextList, emp.Name, min(dTextList,",")).
But it is cool to see various ways to do this. Thank you for all the response

Answer 6

This results in no leading comma (delimiter) and no fiddling with trim/substring/etc
def var cDelim as char.
def var dTextList as char.
cDelim = ''.
for each emp no-lock:
dTextList = dTextList + cDelim + emp.Name.
cDelim = ','.
end.