StrUtils.LeftStr、StrUtils.RightStr - 提取左右字符串
举例:
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var
ss,s: string;
begin
ss := 'CodeGear Delphi 2007';
s := RightStr(ss,4);
ShowMessage(s); {2007}

s := LeftStr(ss,4);
ShowMessage(s); {Code}
end;