oc随笔五：NSArray

#import <Foundation/Foundation.h>

int main(int argc, const char * argv[]) {
@autoreleasepool {
//NSArray的初始化以及常用数组操作方法简单归纳
//不可变数组
//数组的元素只能是对象，如果是int和float的话，就用NSNumber转换一下才能用
//初始化的几种方式，可以一个元素、多个元素、从已有组复制、从文件、网址等
NSArray *arr1 = [NSArray arrayWithObject:@"hello"];
for (id a in arr1) {
NSLog(@"%@",a);
}
//向数组对象初始化赋值，这里可以写任意对象的指针，结尾必须使用nil
NSArray *arr2 = [NSArray arrayWithObjects:@"hello",@"world", nil];
for (id b in arr2) {
NSLog(@"%@",b);
}
//定义指定类型的数组
NSString *str[3];
NSNumber *num[3];
//初始化数组元素赋值
str[0] = @"hello";
str[1] = @"world";
str[2] = @"!";
num[0] = [[NSNumber alloc] initWithInt:1];
num[1] = [[NSNumber alloc] initWithInt:2];
num[2] = [[NSNumber alloc] initWithInt:3];
NSArray *arr3 = [NSArray arrayWithObjects:str count:3];
NSArray *arr4 = [NSArray arrayWithObjects:num count:3];
//遍历数组方法一
for (id strr in arr3) {
NSLog(@"%@",strr);
}
//遍历数组方法二
for (int i = 0; i < [arr4 count]; i++) {
NSLog(@"%@",[arr4 objectAtIndex:i]);
}
//复制数组
NSArray *arr5 = [NSArray arrayWithArray:arr4];
for (NSNumber *c in arr5) {
NSLog(@"%@",c);
}
//给数组增加新元素(对象)
NSArray *newArr5 = [arr5 arrayByAddingObject:@"Augus"];
for (int i = 0 ; i < [newArr5 count]; i++) {
if (i == [newArr5 count] - 1) {
NSLog(@"%@",[newArr5 objectAtIndex:i]);
}
}
//把数组里元素利用连接符连接成字符串
NSString *strNew = [arr5 componentsJoinedByString:@"-"];
NSLog(@"%@",strNew);
//查询数组中是否包含某一元素，YES和NO
BOOL isContain = [arr3 containsObject:@"hello"];
NSLog(@"%d",isContain);
//查询并返回位置，如没有则为NSNotFound
NSInteger index = [arr3 indexOfObject:@"!"];
NSString *indexF = [NSString stringWithFormat:@"%ld",index];
NSInteger indexN = [indexF integerValue];//类型转换
NSLog(@"%ld",indexN);
//获取最后一个元素
NSString *lastEle = [arr3 lastObject];
NSLog(@"%@",lastEle);
//可变数组，5个元素
NSMutableArray *mutArr = [[NSMutableArray alloc] initWithCapacity:5];
//添加一个元素
[mutArr addObject:@"hello"];
[mutArr addObject:[NSNumber numberWithInt:66]];
[mutArr addObject:@"Augus"];
[mutArr addObject:[NSNumber numberWithDouble:19.9]];
//指定位置插入一个元素
[mutArr insertObject:@"world" atIndex:1];
//移除数组的元素，按名称、按序号等
NSLog(@"%@",mutArr);
[mutArr removeLastObject];
NSLog(@"%@",mutArr);
//替换元素
[mutArr replaceObjectAtIndex:2 withObject:@"!"];
NSLog(@"%@",mutArr);
//把一个数组添加到另一个里,实际上就是把数组里的元素都添加进去了
[mutArr addObjectsFromArray:arr4];
NSLog(@"%@",mutArr);
NSLog(@"%ld",[mutArr count]);
}
return 0;
}