Remove spaces and line breaks in iOS string

In iOS, remove the space in the string and line breaks in two cases, the first one is to remove the end of the string of spaces and line breaks, the second is to remove the occurrence of space and line breaks in the string. The code is as follows;

<span style= "FONT-SIZE:18PX;" >    //Remove the spaces and newline characters in the string
    str = [str stringbyreplacingoccurrencesofstring:@ "" withstring:@ "];
    str = [str stringbyreplacingoccurrencesofstring:@ "\ r \ n" withstring:@ "]; line breaks are \ r \ n rather than \
    NSLog (@ "str:%@", str);
    
    Remove the trailing spaces and strings of the string
    str = [str stringbytrimmingcharactersinset:[nscharacterset whitespaceandnewlinecharacterset]] ;
    NSLog (@ "_______str:%@", str);</span>