swapcase method
Return a String
where all the upperCase letters are converted to lowerCase and vice versa.
Example :
print('tHiS'.swapcase()); // 'ThIs'
print('HeLlO'.swapcase()); // 'hElLo'
Implementation
String swapcase() {
final StringBuffer str = StringBuffer();
for (var char in iterable) {
str.write(char.isUpperCase ? char.toLowerCase() : char.toUpperCase());
}
return isNotEmpty ? str.toString() : this;
}