I need so sort an array with an array inside, something like this:
NSMutableArray * array_example = [[NSMutableArray alloc] init];
[array_example addObject:[NSMutableArray arrayWithObjects:
string_1,
string_2,
string_3,
nil]
];
how can i order this array by the field "string_1" of the array??? any idea how can i do that?
Thanks
For iOS 4 and later, this is easily done using a comparator block:
[array_example sortUsingComparator:^(NSArray *o1, NSArray *o2) {
return (NSComparisonResult)[[o1 objectAtIndex:0] compare:[o2 objectAtIndex:0]];
}];
If you're interested in how blocks work, you can have a look at Apple's Short Practical Guide to Blocks.
If you wish to support iOS 3.x, you'd have to use a custom comparison function:
NSComparisonResult compareArrayFirstElement(NSArray *o1, NSArray *o2) {
return [[o1 objectAtIndex:0] compare:[o2 objectAtIndex:0]];
}
and then use:
[array_example sortUsingFunction:compareArrayFirstElement context:nil];
[[o2 objectAtIndex:0] compare:[o1 objectAtIndex:0]] insteadYou can loop the array objects and call sortedArrayUsingSelector on each sub array, then replaceObjectAtIndex:withObject to inject back into the original array
NSMutableArray * array_example = [[NSMutableArray alloc] init];
[array_example addObject:[NSMutableArray arrayWithObjects:
@"z",
@"a",
@"ddd",
nil]
];
[array_example addObject:[NSMutableArray arrayWithObjects:
@"g",
@"a",
@"p",
nil]
];
NSLog(@"Original Array: %@", array_example);
for(int i = 0; i < [array_example count] ; i++){
[array_example replaceObjectAtIndex:i withObject:[[array_example objectAtIndex:i] sortedArrayUsingSelector:@selector(caseInsensitiveCompare:)]];
// order sub array
}
NSLog(@"Sorted Array: %@", array_example);
