/// Returns the character having the minimum frequency.
///
/// If many characters are tied for the minimum frequency, the return value is one of them
/// choosen arbitrarily. If self is empty, return `None`.
Returns the character having the minimum frequency.
If many characters are tied for the minimum frequency, the return value is one of them
choosen arbitrarily. If self is empty, return `None`.
Returns the character having the minimum frequency . If many characters are tied for the minimum frequency the return value is one of them choosen arbitrarily . If self is empty return ` None ` .
fn least_frequent_character(&self) -> Option<char> {
            // compare by the frequency (value) in the ascending order (i.e. the least frequent
            // first), hence "a cmp b".
            self.first_char_sort_by_freq(|a, b| a.cmp(&b))
        }
fn least_frequent_character ( & self ) -> Option < char > { // compare by the frequency (value) in the ascending order (i.e. the least frequent // first), hence "a cmp b". self . first_char_sort_by_freq ( | a , b | a . cmp ( & b ) ) }
Returns the character having the minimum frequency.
Returns the character having the minimum frequency .
&self