Mega Code Archive
Splitting a string in a string list
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Title: Splitting a string in a string list
Question: A function that splits a string in parts separated by a substring
and returns the parts in a StringList
Answer:
Splitting a string in a string list
The following functions split a string in parts separated by a substring and return the parts in a string list that may be passed as third parameter or created by the function (and in this latter case it must be freed by the caller):
interface
uses classes;
function SplitStrings(const str: string;
const separator: string = ',';
Strings: TStrings = nil): TStrings;
function AnsiSplitStrings(const str: string;
const separator: string = ',';
Strings: TStrings = nil): TStrings;
implementation
uses sysutils;
function SplitStrings(const str: string; const separator: string;
Strings: TStrings): TStrings;
// Fills a string list with the parts of "str" separated by
// "separator". If Nil is passed instead of a string list,
// the function creates a TStringList object which has to
// be freed by the caller
var
n: integer;
p, q, s: PChar;
item: string;
begin
if Strings = nil then
Result := TStringList.Create
else
Result := Strings;
try
p := PChar(str);
s := PChar(separator);
n := Length(separator);
repeat
q := StrPos(p, s);
if q = nil then q := StrScan(p, #0);
SetString(item, p, q - p);
Result.Add(item);
p := q + n;
until q^ = #0;
except
item := '';
if Strings = nil then Result.Free;
raise;
end;
end;
function AnsiSplitStrings(const str: string; const separator: string;
Strings: TStrings): TStrings;
// Fills a string list with the parts of "str" separated by
// "separator". If Nil is passed instead of a string list,
// the function creates a TStringList object which has to
// be freed by the caller
// ANSI version
var
n: integer;
p, q, s: PChar;
item: string;
begin
if Strings = nil then
Result := TStringList.Create
else
Result := Strings;
try
p := PChar(str);
s := PChar(separator);
n := Length(separator);
repeat
q := AnsiStrPos(p, s);
if q = nil then q := AnsiStrScan(p, #0);
SetString(item, p, q - p);
Result.Add(item);
p := q + n;
until q^ = #0;
except
item := '';
if Strings = nil then Result.Free;
raise;
end;
end;
Examples:
procedure TForm1.Button1Click(Sender: TObject);
begin
SplitStrings(Edit1.Text, ', ', ListBox1.Items);
end;
procedure TForm1.Button2Click(Sender: TObject);
var
Parts: TStrings;
begin
Parts := nil;
try
Parts := SplitStrings(Edit1.Text, ', ');
ShowMessage('First part is "' + Parts[0] + '"');
finally
Parts.Free;
end;
end;
You can see an example using a dynamic array instead of a StringList in a separate article.
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