iOS中NSArray数组常用处理方式

1. 数组的常用处理方式

//--------------------不可变数组
//1.数组的创建
nsstring *s1 = @"zhangsan";
nsstring *s2 = @"lisi";
nsstring *s3 = @"wangwu";
//(1)
nsarray *array1 = [[nsarray alloc] initwithobjects:s1,s2,s3, nil];
nslog(@"%@",array1); //等价于 array1.descripton
//(2)使用类方法创建
nsarray *array2 = [nsarray arraywithobjects:s1,s2,s3, nil];
//(3)创建一个数组对象，同时往里面存入一元素
nsarray *array3 = [nsarray arraywithobject:s1];
//(4)创建一个数组，此数组中的元素来自array1
nsarray *array4 = [nsarray arraywitharray:array1];
nslog(@"array4 = %@",array4);
//2.通过下标取元素
nsstring *str1 = [array4 objectatindex:0];
//3.数组元素的个数
nsuinteger count = [array4 count]; //等价于：array4.count;
//4.判断数组中的是否包含某个元素
bool iscontains = [array4 containsobject:@"zhangsan"];
nslog(@"iscontains:%d",iscontains);
//5.查找某一个对象在数组中的下标位置
nsuinteger index = [array4 indexofobject:@"wangwu"];
if (index == nsnotfound) {
nslog(@"not find elemnts");
} else {
nslog(@"index = %ld",index);
}
//6.链接数组中的字符串(前提：数组中都是字符串）
nsstring *joinstring = [array4 componentsjoinedbystring:@","];
nslog(@"joinstring = %@",joinstring);
//7.访问数组最后一个元素
nsstring *lastobj = [array4 lastobject]; //array4.lastobject
nslog(@"lsatobj = %@",lastobj);
//8.再原路的数组后面添加一个元素
nsarray *array5 = [array4 arraybyaddingobject:@"zhaolia"];
nslog(@"array5 = %@",array5);
//取对应下标元素
int idx=4;
if (idx <array5.count) {
nsstring *s = [array5 objectatindex:idx];
nslog(@"s = %@",s);
}
//--------------数组的遍历
//1.普通遍历
for (int i=0; i<array5.count; i++) {
nsstring *str = [array5 objectatindex:i];
nslog(@"%@",str);
}
//快速遍历
for (nsstring *s in array5) {
nslog(@"%@",s);
}
//4.4之后的优化
//1.创建一个素组
nsarray *array7 = @[s1,s2,s3]; //等价于：nsarray *array7 = [nsarray arraywithobjects:s1,s2,s3,nil];
nslog(@"array7 = %@",array7);
nsstring *str = array7[0];
nslog(@"array[7] = %@",str);
//------------------可变数组
//初始化，设定元素个数为5，可以更改的。（继承自nsarray）
nsmutablearray *mutablearray = [nsmutablearray arraywithcapacity:5];
//想数组中添加一个元素
[mutablearray addobject:@"aaa"];
//向数组中指定下标插入元素
[mutablearray insertobject:@"ccc" atindex:0];
nslog(@"%@",mutablearray); //原来位置元素后移
//移除最后一个元素
[mutablearray removelastobject];
nslog(@"移除最后元素后：%@",mutablearray);
//移除指定元素
[mutablearray removeobject:@"aaa"];
//移除指定下标元素
[mutablearray removeobjectatindex:0];
//向数组中添加数组
[mutablearray addobjectsfromarray:array1];
//1.创建可变数组
nsstring *t1 = @"zhangsan ";
nsstring *t2 = @"lisi";
nsstring *t3 = @"wangwu ";
// nsmutablearray *marray1 = @[s1,s2,s3];//wrong.这里创建了一个不可变数组
nsmutablearray *marray1 = [[nsmutablearray alloc] initwithobjects:s1,s2,s3, nil];
//创建数组时，开辟3个空间用于存储元素，存储超过容量，数组自动增大空间
nsmutablearray *marray2 = [[nsmutablearray alloc] initwithcapacity:3];
nsmutablearray *marray3 = [nsmutablearray arraywithcapacity:3];
//2.添加元素
[marray2 addobject:t1];
[marray2 addobject:t2];
[marray2 addobject:t3];
nslog(@"marray2= %@",marray2);
//将marray2 中元素添加到marray3中
// [marray3 addobjectsfromarray:marray2];
//将marray2作为二维数字添加
[marray3 addobject:marray2];
nslog(@"marray3 = %@",marray3);
//3.插入元素
[marray2 insertobject:@"jack" atindex:0];
nslog(@"marray2 = %@",marray2);
//4.替换元素
[marray2 replaceobjectatindex:0 withobject:@"john"];
nslog(@"替换：%@",marray2);
//5.互换两个元素的位置
[marray2 exchangeobjectatindex:3 withobjectatindex:0];
nslog(@"marray2 = %@",marray2);
//6.删除元素
//6.1根据下标删除
[marray2 removeobjectatindex:2];
nslog(@"marray2 = %@",marray2);
//6.2删除最后一个元素
[marray2 removelastobject];
nslog(@"marray2 = %@",marray2);
//6.3删除指定的对象
//[marray2 removeobject:@"zhangsan"];
//6.4删除所有元素
[marray2 removeallobjects];
nslog(@"marray2 = %@",marray2);

以上所述是小编给大家介绍的ios中nsarray数组常用处理方式，希望对大家有所帮助