I have an iOS app with a `NSMutableArray` which contains many rows worth of data (split up into 3 segments) - as shown below:

```
[PFUser object, stringData, floatValue]
       .             .          4.3
       .             .          5.9
       .             .          1.1
       .             .          9.32
       .             .          0.024

```

The above diagram shows how the array is split up and the data types that are stored in the array. But those data types are not keys or anything. So I can't do something like `valueForKey`.

An example of what the array looks like:

```
@[@[userObject, @"hello", @234.1441],
  @[userObject, @"sdfsg", @94.33],
  @[userObject, @"wrfdo", @24.897]
];

```

So from the example above you can see that I have arrays in arrays.

I would like to sort the array by reading the 3 segment which contains the float values.

How can I do this? I have looked online and read a lot about using `NSSortDescriptor` but the problem I have is that all the examples always seem to use simple strings or an array with numbers only.

Is there a way to use `NSSortDescriptor` in an array with custom objects like mine?