NSArray NSMutableArray NSString NSMutableString NSDictionary NSMutableDictionary常用增删查改

#program notice - 数组常用方法:(增删查改)

//创建一个多对象数组
NSArray *array = [NSArray arrayWithObjects];

//从一个文件中读取一个数组
+ (NSArray *) arrayWithContentsOfFile:(NSString *)path; 

//返回一个数组的元素个数
- (NSUInteger) count;

//根据index返回元素对象;
- (id) objectAtIndex:(NSUInteger)index;

//第一个元素对象
- (id) firstObject;

//最后一个元素对象
- (id) lastObject;

//判断两个数组元素内容是否相同
- (BOOL) isEqualToArray:(NSArray *)array;

#program notice - NSMutableArray

//可变数组增加元素
- (void) addObject:(id)obj;

//移除index位置上的元素
- (void) removeObjectAtIndex:(NSUInteger)index;

//清空数组
- (void) removeAllObjects;

//移除最后一个元素对象
- (void) removeLastObject;


#program notice - NSMutableString methods;

//追加字符串
- (void) appendFormat:(NSString *)string;

//重置字符串
- (void) setString:(NSString *)string;

//格式化初始字符串
- (id) initWithFormat:();

//从文件中读取一个字符串
- (id) initWithContentsOfFile:(NSString *)path encoding:() error:;

//从URL中读取一个字符串
- (id) initWithContentsOfURL:(NSString *)URL encoding:() error:;

//获取字符串长度,字符个数
- (NSUInteger) length;

//返回C风格字符串
- (NSString *) UTF8String;

//格式化拼接字符串
- (NSString *) stringByAppendingFormat:();

//从index开始获取以后全部子串
- (NSString *) subStringFromIndex:(NSUInteger)index;

//获取子串直到index位置
- (NSString *) subStringToIndex:(NSUInteger)index;

-(NSString *) subStringWithRange:(NSRange)range;

//按指定分隔符分割字符串
- (NSArray *) componentsSeparatedByString:(NSString *)separateString;

#Program notice String Replace

//替换字符串
- (NSString *) stringByReplacingOccurrencesOfString:(NSString *)string withString:(NSString *)string;

//范围替换字符串
- (NSString *) stringByReplacingOccurrencesOfString:(NSString *)string withString:(NSString *)string options:(NSEnum)enumVal range:(NSRange) range;

//比较俩字符串
- (NSCompareVal) compare:(NSString *)string;

//字符串是否以某个字符串开头
- (BOOL) hasPreFix:(NSString *)string;

//字符串是否以某个字符串结尾
- (BOOL) hasSuffix:(NSString *)string;


#Program NOTICE - Getting Numeric Values All Methods
#Program NOTIC - NSDictionary
//初始化多个 < value - key > 用nil结束录入 并且 key一定不能为空 ,若val要为空不能使用nil而要使用NSNull
NSDictionary *dic = [NSDictionary dictionaryWithObjectsAndKeys:@"val_1",@"key_1",@"val_2",
@"key_2",@"val_3",@"key_3",nil];
//返回字典KV个数
- (NSUInteger) count;                                                                                                                                                                                                                                                   
//取出所有key并放入数组
- (NSArray *) allKeys;
//返回所有Value的数组
- (NSArray *) allValues;     
//根据key获得val
- (id) objectForKey:(NSString *)key;
//sorting….
#Program notice - NSMutableDictionary
+ (NSMutableDictionary *) dictionaryWithCapacity:(NSUInteger)capacity;
- (NSMutableDictionary *) initWithCapacity:(NSUInteger)capacity;
- (void) setObject:(id)obj forKey:(NSString *)aKey;
- (void) removeObjectForKey:(NSString *)aKey;
- (void) removeAllObjects;
#Program Notice - NSSet 
NSSet *set = [NSSet setWithObjects:obj1,obj2,nil];