When using text variables are usually declared as Strings. A number of component properties are also string (text) values. For example Button1.Caption or Edit1.Text.

For example sSourceText can be declared as String under var.
sSourceText := ‘The man walks’

Take note that each character in a String variable can be referred to by using an index. The character sSourceText[2] would for instance be 'h'.

Even the spaces therefore has index values (see characters 4 and 8 above).


Furthermore Delphi has a number of prewritten functions and procedures that can be used to get properties of String variables or to manipulate the variables. Therefore to:

• Determine the position of a piece of a text within a string
  IntegerVariable := Pos(StrToBeFound, SourceText);
  For example: iX := Pos (‘m’, sSourceText);
  {The value of iX is now: 5}
   
• Display a certain character within a string using square brackets at the end of a variable.
  StringVariable := SourceText[CharacterPosition];
  For example: sNewText := sSourceText[2];
  {The value of sNewText is now: ‘h’}
   
• Display a certain section of text within a string.
  For example: StringVariable := Copy(SourceText, BeginPosition, Length);
  sNewText := Copy(sSourceText, 5, 3);
  {The value of sNewText is now: ‘man’}
   
• Insert a certain section of text within a string.
  For example: Insert(InsertText, SourceText, Position);
  Insert(‘big ’, sSourceText, 5);
  {The value of sSourceText is now: ‘The big man walks’}
   
• Remove a certain section of text within a string.
  For example: Delete(SourceText, Position, Length);
  Delete(sSourceText, 5, 4);
  {The value of sSourceText is now: ‘The walks’}
   
• Determine the length of a string.
  For example: IntegerVariable := Length(SourceText);
  iX := Length(sSourceText);
  {The value of iX is now: 13}
   
• Change the whole string to lowercase.
  For example: LowerCase(SourceText);
  LowerCase(sSourceText);
  {The value of sSourceText is now: ‘the man walks’}
   
• Change the whole string to uppercase.
  For example: UpperCase(SourceText);
  UpperCase(sSourceText);
  {The value of sSourceText is now: ‘THE MAN WALKS’}
  Take note: Use UpCase for Char type.