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1.数组的创建
OC中数组存储对象的地址
对象方法初始化
1 NSArray * arr1 = [[NSArray alloc] initWithObjects:@"one",@"two",@"three", nil];
2
3 NSLog(@"%@",arr1);
类方法初始化
1 NSArray * arr2 = [NSArray arrayWithObjects:@"one",@"two",@"three", nil];
创建数组时以nil结束
使用@[]初始化
1 NSArray * arr3 = @[@"one",@"two",@"three"];
2.数组存储基本数据类型 oc数组存储的是对象的地址 所以需要将基本数据类型的变量转变为对象的地址
numberWithInt:(int) numberWithFloat:(float) numberWithDouble:(double）
1 int age = 25;
2 NSNumber * num = [NSNumber numberWithInt:age];
3 NSArray * arr5 = @[@"one",@"two",@"three",num];
4 NSLog(@"%@",arr5);
3.数组中可以存放自定义对象
1 Person * p1 = [[Person alloc] initWithName:@"Tom" andAge:18];
2 Person * p2 = [[Person alloc] initWithName:@"Lilei" andAge:20];
3 Person * p3 = [[Person alloc] initWithName:@"Lily" andAge:25];
4
5 NSArray * arr6 = @[p1,p2,p3];
1 #import <Foundation/Foundation.h>
2
3 @interface Person : NSObject {
4 NSString * _name;
5 int _age;
6
7 }
8 - (id)initWithName:(NSString *)name andAge:(int)age;
9 @end
1 #import "Person.h"
2
3 @implementation Person
4 - (id)initWithName:(NSString *)name andAge:(int)age {
5 if (self = [super init]) {
6 _name = name;
7 _age = age;
8 }
9 return self;
10 }
11
12 - (NSString *)description {
13 return [NSString stringWithFormat:@"name:%@ age:%d",_name,_age];
14 }
15
16 @end
- (NSString *)description； 该方法返回值即为打印数组时打印的字符串。
5.获取数组中的对象
1 Person * p4 = [arr6 objectAtIndex:2]; 2 NSLog(@"p4 %@",[p4 description]);
6.获取数组中的个数
1 NSUInteger count = [arr6 count];
7.判断是否包含元素
判断的是内容 而非地址
1 Person * p5 = [[Person alloc] initWithName:@"Jack" andAge:28];
2 BOOL isContain = [arr6 containsObject:p5];
3
4 if (isContain) {
5 NSLog(@"包含");
6 } else {
7 NSLog(@"不包含");
8 }
9
10 NSString * str1 = [[NSString alloc] initWithFormat:@"one"];
11 NSArray * arr7 = @[@"one",@"two",@"three"];
12 BOOL isContain1 = [arr7 containsObject:str1];
13
14 if (isContain1) {
15 NSLog(@"包含");
16 } else {
17 NSLog(@"不包含");
18 }
8.数组排序
1 // @selector
2 NSArray * arr = @[@"a",@"g",@"f",@"d",@"e"];
3
4 // YES 左边 > 右边
5 // 左边 < 右边
6 BOOL isGreater = [@"b" isGreaterThan:@"a"];
7 NSLog(@"isGreater %d",isGreater);
8
9 // SEL sel = @selector(isGreaterThan:);
10 NSLog(@"before %@",arr);
11 // NSArray * arr2 = [arr sortedArrayUsingSelector:sel];
12 NSArray * arr2 = [arr sortedArrayUsingSelector:@selector(isGreaterThan:)];
13 NSLog(@"after %@",arr2);
14
15 // @selector
16 // Block
17 // 声明: 返回值 (^名字)(参数列表) = ^返回值 (参数列表) {
18
19 // }
20 NSComparisonResult (^block)(id obj1,id obj2) = ^NSComparisonResult(id obj1, id obj2) {
21 return [obj1 compare:obj2];
22 };
23
24 // Block
25 NSArray * arr3 = [arr sortedArrayUsingComparator:block];
26
27 [arr sortedArrayUsingComparator:^NSComparisonResult(id obj1, id obj2) {
28 return [obj1 isLessThan:obj2];
29 }];
30 NSLog(@"after arr3 %@",arr3);
@selector 传入一个方法名 也就是方法的地址
Block
声明: 返回值 (^名字)(参数列表) = ^返回值 (参数列表) {
操作
}
9.可变数组
9.1 可变数组
1 NSArray * arr1 = @[@"one",@"two",@"three"];
2
3 NSMutableArray * muarr1 = [[NSMutableArray alloc] initWithArray:arr1];
4
5 NSMutableArray * muarr2 = [[NSMutableArray alloc] initWithObjects:@"one",@"two",@"three", nil];
NSMutableArray * muarr3 = @[@"one",@"two",@"three"]; 并不能这样写
9.2重置数组 1 [muarr2 setArray:@[@"one"]]; 2 NSLog(@"%@",muarr2);
9.3添加元素 1 [muarr2 addObject:@"two"];
1 NSArray * arr2 = @[@"a",@"b",@"c"];
2 // 把数组作为对象添加到数组中
3 [muarr2 addObject:arr2];
9.4插入元素
1 // 插入对象
2 [muarr2 insertObject:@"z" atIndex:1];
3 [muarr2 addObject:@"one"];
4 NSLog(@"%@",muarr2);
9.5删除元素
// 删除
// 会通过对象地址,删除数组中所有的同一个地址的对象
[muarr2 removeObject:@"one"];
NSLog(@"%@",muarr2);
// 删除 指定位置的对象
[muarr2 removeObjectAtIndex:1];
NSLog(@"%@",muarr2);
// 删除全部对象
[muarr2 removeAllObjects];
NSLog(@"%@",muarr2);
10.遍历数组
[arr count]为数组的元素数
[arr objectAtIndex:i] 为index处的元素
1 NSArray * arr = @[@"英雄联盟",@"跑跑卡丁车",@"红色警戒"];
2 NSLog(@"%@",arr);
3
4 NSString * str = arr[0];
5 NSLog(@"%@",str);
6 for (int i = 0; i < [arr count]; i++) {
7 NSLog(@"%@",[arr objectAtIndex:i]);
8 }
9 // 快速枚举
10 for (NSString * str in arr) {
11 NSLog(@"%@",str);
12 }
11.字符串与数组的相互转换
1 NSString * str = @"I am a teacher";
2 //componentsSeparatedByString: 用字符串来分割 用数组存储
3
4 NSArray * arr = [str componentsSeparatedByString:@" "];
5 NSLog(@"%@",arr);
6
7 NSString * str2 = @"a";
8 NSArray * arr1 = [str2 componentsSeparatedByString:@"a"];
9 NSLog(@"%@",arr1);
10
11 //componentsJoinedByString 用字符串拼接数组元素 范围一个新字符串
12 NSString * str3 = [arr componentsJoinedByString:@"-"];
13 NSLog(@"%@",str3);
附加 @selector语法
1 int main(int argc, const char * argv[]) {
2 @autoreleasepool {
3 NSLog(@"%d",cal(3,5, add));
4
5 Dog * dog = [[Dog alloc] init];
6 // [dog bark];
7
8 [dog eatAfterSel:@selector(rockTail)];
9
10
11
12 }
13 return 0;
14 }
1 #import <Foundation/Foundation.h>
2
3 @interface Dog : NSObject
4 - (void)bark;
5 - (void)rockTail;
6 - (void)eat;
7 - (void)eatAfterSel:(SEL)sel;
8
9 @end
1 #import "Dog.h"
2
3 @implementation Dog
4 - (void)bark {
5 NSLog(@"wangwang");
6 }
7
8 - (void)rockTail {
9 NSLog(@"狗在深情地摇着尾巴");
10 }
11
12 - (void)eat {
13 NSLog(@"狗在吃屎");
14 }
15
16
17 - (void)eatAfterSel:(SEL)sel {
18 [self performSelector:sel];
19 [self eat];
20 }
21 @end
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原文地址：http://www.cnblogs.com/gwkiOS/p/4924653.html
