NSSortDescriptor数组排序

NSSortDescriptor可以实现对数组的排序，经常可用于按照首字母进行排序等。

按照升序或者降序，比如@"e",@"a",@"c",@"b"按照生序顺序为@"a",@"b",@"c",@"e"。

将@"3",@"1",@"4",@"0",@"2",@"10",@"22"按照升序列为：@"0",@"1",@"10",@"2",@"22",@"3",@"4"。

用到的方法

- (NSArray *)sortedArrayUsingDescriptors:(NSArray *)sortDescriptors;    // returns a new array by sorting the objects of the receiver

- (NSArray *)sortedArrayUsingDescriptors:(NSArray *)sortDescriptors;    // returns a new array by sorting the objects of the receiver

ascending为升序或者降序，YES为升序。

按照首数字顺序排序

NSMutableArray *datasource = [[NSMutableArray alloc] init];
[datasource addObjectsFromArray:@[@"3",@"1",@"4",@"0",@"2",@"10",@"22"]];

NSSortDescriptor *descriptor = [NSSortDescriptor sortDescriptorWithKey:@"self" ascending:YES];

NSArray *newArray = [datasource sortedArrayUsingDescriptors:[NSArray arrayWithObjects:descriptor, nil]];

for (NSString *distance in newArray) {
    NSLog(@"%@", distance);
}

打印结果：

2017-09-04 17:07:09.768 Test——1[93764:646098] 0
2017-09-04 17:07:09.768 Test——1[93764:646098] 1
2017-09-04 17:07:09.768 Test——1[93764:646098] 10
2017-09-04 17:07:09.768 Test——1[93764:646098] 2
2017-09-04 17:07:09.768 Test——1[93764:646098] 22
2017-09-04 17:07:09.769 Test——1[93764:646098] 3
2017-09-04 17:07:09.769 Test——1[93764:646098] 4

按照首字母排序

NSMutableArray *datasource = [[NSMutableArray alloc] init];
[datasource addObjectsFromArray:@[@"meng",@"xaing",@"bian",@"jian",@"bo",@"wang",@"wan"]];

NSSortDescriptor *descriptor = [NSSortDescriptor sortDescriptorWithKey:@"self" ascending:YES];

NSArray *newArray = [datasource sortedArrayUsingDescriptors:[NSArray arrayWithObjects:descriptor, nil]];

for (NSString *distance in newArray) {
    NSLog(@"%@", distance);
}

结果：

2017-09-04 17:34:56.268 Test——1[93969:655792] bian
2017-09-04 17:34:56.268 Test——1[93969:655792] bo
2017-09-04 17:34:56.268 Test——1[93969:655792] jian
2017-09-04 17:34:56.268 Test——1[93969:655792] meng
2017-09-04 17:34:56.269 Test——1[93969:655792] wan
2017-09-04 17:34:56.269 Test——1[93969:655792] wang
2017-09-04 17:34:56.269 Test——1[93969:655792] xaing

按照key排序

NSMutableArray *datasource = [[NSMutableArray alloc] init];

NSMutableDictionary *dic1 = [[NSMutableDictionary alloc] init];
[dic1 setObject:@"zhangfei" forKey:@"name"];

NSMutableDictionary *dic2 = [[NSMutableDictionary alloc] init];
[dic2 setObject:@"libai" forKey:@"name"];

NSMutableDictionary *dic3 = [[NSMutableDictionary alloc] init];
[dic3 setObject:@"dufu" forKey:@"name"];

[datasource addObject:dic1];
[datasource addObject:dic2];
[datasource addObject:dic3];

NSSortDescriptor *descriptor = [NSSortDescriptor sortDescriptorWithKey:@"name" ascending:YES];

NSArray *array = [datasource sortedArrayUsingDescriptors:[NSArray arrayWithObjects:descriptor, nil]];

for (NSMutableDictionary *md in array) {
    NSLog(@"%@", [md objectForKey:@"name"]);
}

打印结果

2017-09-04 17:43:05.833 Test——1[94084:659345] dufu
2017-09-04 17:43:05.833 Test——1[94084:659345] libai
2017-09-04 17:43:05.833 Test——1[94084:659345] zhangfei