block 数组排序

#import <Foundation/Foundation.h>

//定义⼀一个block,返回值为BOOL,有两个NSString参数。实现:判

//断字符串是否相等。

BOOL (^compareString)(NSString *, NSString *) = ^(NSString *str1, NSString *str2){

if ([str1 isEqualToString:str2]) {

return YES;

}else{

return NO;

}

};

if (compareString(@"sss",@"sss")) {

NSLog(@"相同");

}

//定义⼀一个block,返回值为NSInteger,有两个参数,⼀一个是 NSArray,⼀一个是NSString。实现:判断数组时候包含此字符串,如 果包含,返回字符串的下标,如果不包括,返回-1。

NSArray *arr = @[@"aa",@"ss",@"ww"];

NSString *str = @"ss";

int (^find)(NSArray *, NSString *) = ^(NSArray *arr, NSString *str ){

for (int i = 0; i < arr.count; i++) {

if ([arr[i] isEqualToString:str]) {

return i;

}

}

return -1;

};

int f = find(arr,str);

NSLog(@"%d",f);

//创建⼀一个数组,初始化为@“123",@"21",@"33",@"69", @“108”,

//@“256”。使⽤用Block语法,进⾏行数组的排序。并输出内容。 排序结果:108 123 21 256 33 69

//提⽰示:sortedArrayWithOptions:usingComparator:

//不可变数组

NSArray *arr1 = @[@"23", @"1", @"3", @"2", @"108"];

NSArray *arr2 = [arr1  sortedArrayUsingComparator:^NSComparisonResult(id obj1, id obj2){

if ([obj1 intValue] > [obj2 intValue]) {

return NSOrderedDescending;

}

return NSOrderedSame;

}

];

NSLog(@"sortArray1:%@", arr2);

NSArray *arr11 = @[@"23", @"1", @"3", @"2", @"108"];

NSArray *a1 = [arr11  sortedArrayUsingComparator:^NSComparisonResult(id obj1, id obj2){

if ([obj1 intValue] > [obj2 intValue]) {

return NSOrderedDescending;

}

return NSOrderedSame;

}];

NSLog(@"sortArray1:%@", a1);

//5, 给可变数组排序的block

//5,1

NSComparator sortBlock = ^(id string1, id string2)

{

return [string1 compare:string2];

};

NSMutableArray *stringArray = [NSMutableArray arrayWithObjects:@"g", @"c", @"b", @"a",nil];

NSArray *a = [stringArray sortedArrayUsingComparator:sortBlock];

NSLog(@"Array:%@", a);

//分开写的block 不可变数组

NSComparator sortBlock1 = ^(id string1, id string2)

{

return [string1 compare:string2];

};

NSArray *stringArray2 = [NSArray arrayWithObjects:@"g", @"c", @"b", @"a",nil];

NSArray *a2 = [stringArray2 sortedArrayUsingComparator:sortBlock1];

NSLog(@"分开写的block 可变数组:%@", a2);

//4. 使用Block根据Person的age进行排序，并输出

[array sortUsingComparator:^NSComparisonResult(Person *p1 ,Person *p2){

if([p1 age] > [p2 age])

return NSOrderedDescending;

else

return NSOrderedSame;
    }];

/*

//根据年龄 升序排列

[array sortUsingComparator:^NSComparisonResult(id p1, id p2){

if ([p1 age] > [p2 age]) {  //  <:降序.     >:升序

return NSOrderedDescending;

}

return NSOrderedSame;

}];

*/