Delphi : Copy specific lines from Stringlist to another - text

Question

I'm getting an "Index limit out of bonds" error when I try to copy specific strings by index from one TStringList to another.
I have a text file that contain lines formatted with a pipe "|" delimiter. It looks like this:
In my destination file, I want to copy only some items from lines that start with '3M', in order to get something like this (the first line, for example):
3M 2189300002 12.99
3M is Stringlist.strings[1]
2189300002 is Stringlist.strings[3]
12.99 is Stringlist.strings[6]
Here is my code:
var
sl,new : tstringlist;
lscount,index : integer;
begin
sl:= TStringList.Create;
sl.LoadFromFile('C:\Folder\test.txt');
new := tstringlist.create;
lscount := lstringlist.Count;
for index := 0 to lscount do
begin
sl.delimiter := '|';
sl.StrictDelimiter := True;
sl.DelimitedText := sl.Strings[index];
if sl.Strings[1] = '3M' then
new.Add(sl.Strings[1]+sl.Strings[3]+sl.Strings[6]);
end;
new.SaveToFile('C:\Folder\new.txt');
sl.Free;
new.Free
end;
What's wrong with my code?

Answer 1

There are quite a number of mistakes in your code.
Your for loop is looping from index 0 to lscount, but the upper bound of the TStringList is lscount-1 instead.
You are modifying sl while you are looping through sl. You need to use a separate TStringList when parsing each line.
You are accessing the parsed strings using 1-based indexes, but TStringList uses 0-based indexes instead.
Try something more like this:
var
sl, parse, new : TStringList;
index : Integer;
begin
sl := TStringList.Create;
try
sl.LoadFromFile('C:\Folder\test.txt');
new := TStringList.create;
try
parse := TStringList.Create;
try
parse.Delimiter := '|';
parse.StrictDelimiter := True;
for index := 0 to sl.Count-1 do
begin
parse.DelimitedText := sl.Strings[index];
if (parse.Count > 5) and (parse.Strings[0] = '3M') then
new.Add(parse.Strings[0] + ' ' + parse.Strings[2] + ' ' + parse.Strings[5]);
end;
finally
parse.Free;
end;
new.SaveToFile('C:\Folder\new.txt');
finally
new.Free;
end;
finally
sl.Free
end;
end;