NSArray常用函数

/**** NSArray ****/ 

/*---------------------------创建数组------------------------------*/ 

NSArray *array = [[NSArray alloc] initWithObjects: @"One",@"Two",@"Three",@"Four",nil];
NSArray * array1 = [[NSArray alloc]initWithArray:array]; NSArray * array2 = [NSArrayarrayWithArray:array]; NSArray *array3 = [[NSArrayarrayWithObjects: @"One",@"Two",@"Three",@"Four",nil]; 

[array release]; [array1 release]; 

//- (NSUInteger) Count;数组所包含对象(元素)个数;NSLog(@"count:%d",[array count]);
//- (id) objectAtIndex: (NSUInteger) index;获取指定索引处的对象(元素);NSLog(@"object :%@",[array objectAtIndex:2]); 

/*查找:根据元素找到对应的索引*/ 

NSArray*array=[[NSArrayalloc]initWithObjects:@"one",@"two",@"three",@"one ", nil];
//返回找到的第一个的索引,一切操作不要越界
NSUInteger index = [array indexOfObject:@"one"]; 

//在指定范围内查找
index = [array indexOfObject:@"one" inRange:NSMakeRange(1, 3)]; if (index != NSNotFound) {//找不到返回 NSNotFound 

NSLog(@"index = %ld",index); } 

/*数组的抽取*/

NSArray * array1 = [array objectsAtIndexes:[NSIndexSet  indexSetWithIndexesInRange:NSMakeRange(1, 3)]];
//NSIndexSet 数字集合类
//[NSIndexSet indexSetWithIndexesInRange:NSMakeRange(1, 3)];创建一个数字集合对象//该集合成员是数字 1,2,3; 

/*枚举器*/ 

//创建一个正序枚举器
NSEnumerator * enume1 = [array objectEnumerator]; //枚举器是读数据的 

while (obj = [enume1 nextObject]) { NSLog(@"%@",obj); 

} 

//快速枚举(正序) 

NSArray *array = [NSArray arrayWithObjects: @"a",@"b",@"c",@"d",nil]; 

for(id obj in array) { 

NSLog(@"obj:%@",obj); 

} 

//创建一个逆序枚举器
NSEnumerator * enume2 = [array reverseObjectEnumerator]; while (obj = [enume2 nextObject]) { 

NSLog(@"obj = %@",obj); } 

/*---------------------字符串分割到数组---------------------*/ 

NSString * str = @" Yes,I am a good man ";
//以字符串整体作为分割条件
NSArray * array = [str componentsSeparatedByString:@" "];//以@” ” 作为分割条件
NSArray*array1 = [str componentsSeparatedByCharactersInSet:[NSCharacterSet characterSetWithCharactersInString:@" ,"]];//以字符作为分割条件//NSCharacterSet字符集合
//[NSCharacterSet characterSetWithCharactersInString:@" ,"];把字符串@" ,"转化为一个字符集合
//这个集合的成员就是字符' '和字符',';
//返回值是 NSArray不要写成 NSMuatbaleArray 

/*---------------------数组元素拼接成字符串---------------------*/ 

NSString * ptr = [array componentsJoinedByString:@"###"];//把数组元素拼接成字符串
NSLog(@”ptr = %@”,ptr);