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;
}];
*/
