//  NSArray * sortedArray = [cache sortedArrayUsingSelector:@selector(compare:)];

 

 {

  NSArray * arr1 = @[@"A",@"B",@"C",@"D"];

    NSArray * arr2 = @[@"1",@"2",@"3"];

    NSArray * arr3 = @[@"x",@"y"];

    NSArray * arr4 = @[@"X",@"Y",@"Z"];

     self.dic = @{@"1":arr1,@"2":arr2,@"3":arr3,@"4":arr4};

}

如上一个字典,取出其中所有的值

NSArray * cache = [self.dic allKeys];

可以对数组中内容格式化输出一下

NSArray * cache = [self.dic allKeys];

打印结果为无序

UIPickerView[2170:124183] (

    3,

    1,

    4,

    2

)

可以通过方法对简单字符串排序

NSArray * sortedArray = [cache sortedArrayUsingSelector:@selector(compare:)];

    NSLog(@"%@",sortedArray);

打印结果为有序