Trimming:

• You can remove in String Whitespace in to use function trim() ,
  Right side to remove String Whitespace in to use function trimRight() ,
  Left Side to remove String white space in to use function trimLeft() .

void main(){
  String str = "  Hello Jeet How are You!  ";

  print(str.trim());

  print(str.trimLeft());

  print(str.trimRight());

}

Output:

Hello Jeet How are You!
Hello Jeet How are You!  
  Hello Jeet How are You!

Padding:

• You can add Padding space in Your String sentence in padding add using padLeft() and padRight() function to use padding set in Your string sentence

void main()
{
  String str1 = "Jeet";

  print(str1.padLeft(10,'--'));

  print(str1.padRight(3));

}

Output:

----------Jeet 
Jeet