Objective-C中NSArray的基本用法示例
NSArray的排序
+(id)studentWithFirstName:(NSString*)firstNamelastName:(NSString*)lastName{
Student*stu=[[Studentalloc]init];
stu.firstName=firstName;
stu.lastName=lastName;
returnstu;
}
+(id)studentWithFirstName:(NSString*)firstNamelastName:(NSString*)lastNamebookName:(NSString*)bookName{
Student*stu=[StudentstudentWithFirstName:firstNamelastName:lastName];
stu.book=[BookbookWithName:bookName];
returnstu;
}
-(NSComparisonResult)compareStudent:(Student*)stu{
NSComparisonResultresult=[self.firstNamecompare:stu.firstName];
if(result==NSOrderedSame){
result=[self.lastNamecompare:stu.lastName];
}
returnresult;
}
-(NSString*)description{
//return[NSStringstringWithFormat:@"%@%@%@",self.firstName,self.lastName,self.book.name];
return[NSStringstringWithFormat:@"%@%@%@",self.firstName,self.lastName,_book.name];
}
#pragmamark3.NSArray排序1
voidarraySort1(){
NSArray*array=[NSArrayarrayWithObjects:@"2",@"3",@"1",@"4",nilnil];
//指定系统自带规定的比较方法compare:
NSArray*array2=[arraysortedArrayUsingSelector:@selector(compare:)];
NSLog(@"%@",array2);
}
#pragmamark3.NSArray排序2
voidarraySort2(){
Student*stu1=[StudentstudentWithFirstName:@"hu"lastName:@"mingtao"];
Student*stu2=[StudentstudentWithFirstName:@"zhu"lastName:@"wenpeng"];
Student*stu3=[StudentstudentWithFirstName:@"zhao"lastName:@"weisong"];
Student*stu4=[StudentstudentWithFirstName:@"hu"lastName:@"junpeng"];
NSArray*array=[NSArrayarrayWithObjects:stu1,stu2,stu3,stu4,nilnil];
//类似JAVA中得compareTo,自己定义比较方式,但是一定要实现compare方法
NSArray*array2=[arraysortedArrayUsingSelector:@selector(compareStudent:)];
NSLog(@"%@",array2);
}
#pragmamark3.NSArray排序3-Block排序
voidarraySort3(){
Student*stu1=[StudentstudentWithFirstName:@"hu"lastName:@"mingtao"];
Student*stu2=[StudentstudentWithFirstName:@"zhu"lastName:@"wenpeng"];
Student*stu3=[StudentstudentWithFirstName:@"zhao"lastName:@"weisong"];
Student*stu4=[StudentstudentWithFirstName:@"hu"lastName:@"junpeng"];
NSArray*array=[NSArrayarrayWithObjects:stu1,stu2,stu3,stu4,nilnil];
NSArray*array2=[arraysortedArrayUsingComparator:^NSComparisonResult(Student*obj1,Student*obj2){
NSComparisonResultresult=[obj1.firstNamecompare:obj2.firstName];
if(result==NSOrderedSame){
result=[obj1.lastNamecompare:obj2.lastName];
}
returnresult;
}];
NSLog(@"%@",array2);
}
#pragmamark4.NSArray排序4-高级排序
voidarraySort4(){
Student*stu1=[StudentstudentWithFirstName:@"hu"lastName:@"mingtao"bookName:@"lianai"];
Student*stu2=[StudentstudentWithFirstName:@"zhu"lastName:@"wenpeng"bookName:@"tianshi"];
Student*stu3=[StudentstudentWithFirstName:@"zhao"lastName:@"weisong"bookName:@"love"];
Student*stu4=[StudentstudentWithFirstName:@"hu"lastName:@"junpeng"bookName:@"qingren"];
NSArray*array=[NSArrayarrayWithObjects:stu1,stu2,stu3,stu4,nilnil];
//1.先按照书名进行排序
NSSortDescriptor*bookNameDesc=[NSSortDescriptorsortDescriptorWithKey:@"book.name"ascending:YES];
//2.先按照姓进行排序
NSSortDescriptor*firstNameDesc=[NSSortDescriptorsortDescriptorWithKey:@"firstName"ascending:YES];
//3.先按照名进行排序
NSSortDescriptor*lastNameDesc=[NSSortDescriptorsortDescriptorWithKey:@"lastName"ascending:YES];
NSArray*array2=[arraysortedArrayUsingDescriptors:[NSArrayarrayWithObjects:bookNameDesc,firstNameDesc,lastNameDesc,nilnil]];
NSLog(@"%@",array2);
}
NSArray的一些用法
NSArray 只允许装OC对象，并且不能装空值，空代表数组元素的结束
#pragmamark-NSArray的基本用法
//创建一个空数组
NSArray*array=[NSArrayarray];
//创建有一个元素的数组
array=[NSArrayarrayWithObject:@"123"];
//创建有多个元素的数组
array=[NSArrayarrayWIthObjects:@"a",@"b",nil];//不能装nil空指针，空值代表数组元素结束
//将一个数组赋值给一个数组
+(instancetype)arrayWithArray:(NSArray*)array;
//获取元素的个数
intcount=[arraycount];//和count=array.count;相同，都是调用get方法
//是否包含一个元素
-(bool)containsObject:(id)anObject;
//返回最后一个元素
-(id)lastObject;
//获取index位置的元素
-(id)objectAtIndex:(NSUInteger)index;
//获取元素的位置
-(NSUInteger)indexOfObject:(id)anObject;
//在range范围内查找元素的位置
-(NSUInteger)indexofObject:(id)anObjectinRange:(NSRange)range;
//比较两个集合内容是否相同
-(Bool)isEqualToArray:(NSArray*)otherArray;
//返回两个集合中第一个相同的对象元素
-(id)firstObjectCommonWithArray:(NSArray*)otherArray;
#pragmamark-NSArray的高级用法 //让集合里面的所有元素都执行aSelector这个方法 -(void)makeObjectsPerformSelector:(SEL)aSelector; //让集合里面的所有元素都执行aSelector这个方法,给这个方法添加参数，但是只支持一个参数 -(void)makeObjectsPerformSelector:(SEL)aSelectorwithObject:(id)argument //添加一个元素，返回一个新的NSArray（方法调用者本身没有发生变化） -(NSArray*)arrayByAddingObject:(id)anObject //添加otherArray的所有元素，返回一个新的NSArray（方法着本身没有改变） -(NSArray*)arrayByAddingObjectsFromArray:(NSArray*)otherArray; //截取range范围的数组 -(NSArray*)subarrayWithRange:(NSRenge)range; //用separator做拼接符，拼接成一个字符串 -(NSString*)componentsJoinedByString:(NSString*)separator //将NSArray持久化到文件中去 -(Bool)writeToFile:(NSString*)pathatomically:(Bool)useAuxiliaryFile
#pragmamark-NSArray的遍历 //方法一：普通遍历(利用for循环) voidarrayFor1(){ NSArray*array=[NSArrayarrayWithObjects:@"1",@"2",@"3",nil]; intcount=array.count; for(inti=0;i<count;i++){ idobj=[arrayobjectAtIndex:i]; NSLog(@"%i-%@",i,obj); } }
//方法二：快速遍历 voidarrayFor2(){ NSArray*array=[NSArrayarrayWithObjects:@"1",@"2",@"3",nil]; intcount=array.count; inti=0; for(idobjinarray){ NSLog(@"%i-%@",i,obj); i++; } }
//方法三：利用block遍历 voidarrayFor3(){ NSArray*array=[NSArrayarrayWithObjects:@"1",@"2",@"3",nil]; [arrayenumerateObjectsUsingBlock:^(idobj,NSUIntegeridx,BOOL*stop){ NSLog(@"%zi->%@",idx,obj); // *stop=YES;//改变外边的Bool，终止遍历 }]; }
//方法四：利用迭代器 先介绍一下-->NSEnumerator迭代器：集合的迭代器，可以用于遍历集合元素,NSArray有相应的方法来获取迭代器 //获取一个正序遍历的迭代器 -(NSEnumerator*)objectEnumerator; //获取一个反序遍历的迭代器 -(NSEnumerator*)reverseObjectEnumerator; @常用方法： //获取下一个元素 -(id)nextObject; //获取所有的元素 -(NSArray*)allObjects voidarrayFor4(){ NSArray*array=[NSArrayarrayWithObjects:@"1",@"2",@"3",nil]; NSEnumerator*enumerator=[arrayobjectEnumerator];//返回数组的迭代器 //如果放到遍历之后，则取到空，原因是，遍历完了，就没值了 NSArray*array2=[enumeratorallObjects]; NSLog(@"array2=%@",array2); //获取下一个需要遍历的元素 idobj=nil; while(obj=[enumeratornextObject]){ NSLog(@"obj=%@",obj); } }