iOS數組里面元素按字母排序

//排序方法
        [self.groupUserArray sortUsingComparator:^NSComparisonResult(GroupUserModel *obj1, GroupUserModel *obj2) {
            NSMutableString *str1 = [obj1.name mutableCopy];
            NSMutableString *str2 = [obj2.name mutableCopy];
            str1 = [self getLatinWithFullName:str1];
            str2 = [self getLatinWithFullName:str2];
            NSComparisonResult result = [str1 compare:str2];
            return result;
        }];

//優化速度
- (NSString *)getLatinWithFullName:(NSString *)name{
    //1.先從緩存中獲得latin，然后再判斷是否存在，再將非字符串轉化成拉丁字母
    NSString* latin = [self.pinyinDic objectForKey:name];
    if (latin) {
        return latin;
    }else {
        latin = [NSString stringWithString:name];
        CFStringTransform((__bridge CFMutableStringRef)latin, NULL, kCFStringTransformMandarinLatin, NO);
        CFStringTransform((__bridge CFMutableStringRef)latin, NULL, kCFStringTransformStripDiacritics, NO);
        [self.pinyinDic setObject:latin forKey:name];
        return latin;
}