NSString 和NSArray用法大全

2018-07-20    来源:open-open

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一、NSString 
 
创建字符串。 
 
    NSString *astring = @"This is a String!";  
 
创建空字符串,给予赋值。 
 
    NSString *astring = [[NSString alloc] init];  
      
    astring = @"This is a String!";  
      
    NSLog(@"astring:%@",astring);  
      
    string release];  
 
使用变量初始化 
 
    NSString *name = @"Ivan!";  
       NSString *astring = [[NSString stringWithFormat:@”My name is %@!”,name]];  
       NSLog(@"astring:%@",astring);  
 
判断是否包含某字符串 
 
检查字符串是否以另一个字符串开头
 
    - (BOOL) hasPrefix: (NSString *) aString;  
         NSString *String1 = @"NSStringInformation.txt";  
         [String1 hasPrefix:@"NSString"] == 1 ?  NSLog(@"YES") : NSLog(@"NO");  
         [String1 hasSuffix:@".txt"] == 1 ?  NSLog(@"YES") : NSLog(@"NO");  
 
是否包含其它字符 
 
    NSString *astring = [[NSString alloc] initWithString:@"This is a String!"];  
    Boolean contains = [astring rangeOfString:@”This”].length>0;  
 
从文件读取字符串:
 
    initWithContentsOfFile方法     
         NSString *path = @"astring.text";  
         NSString *astring = [[NSString alloc] initWithContentsOfFile:path];  
         NSLog(@"astring:%@",astring);  
         [astring release];  
 
写字符串到文件:writeToFile方法  
 
    NSString *astring = [[NSString alloc] initWithString:@"This is a String!"];  
         NSLog(@"astring:%@",astring);  
         NSString *path = @"astring.text";      
         [astring writeToFile: path atomically: YES];  
         [astring release];      
 
比较两个字符串       
 
isEqualToString方法     
 
    NSString *astring01 = @"This is a String!";  
         NSString *astring02 = @"This is a String!";  
         BOOL result = [astring01 isEqualToString:astring02];  
         NSLog(@"result:%d",result);  
 
compare方法(comparer返回的三种值)
 
    NSString *astring01 = @"This is a String!";  
         NSString *astring02 = @"This is a String!";      
         BOOL result = [astring01 compare:astring02] = = NSOrderedSame;      
         NSLog(@"result:%d",result);      
 
NSOrderedSame判断两者内容是否相同 
 
    NSString *astring01 = @"This is a String!";  
         NSString *astring02 = @"this is a String!";  
         BOOL result = [astring01 compare:astring02] = = NSOrderedAscending;      
         NSLog(@"result:%d",result);  
 
不考虑大小写比较字符串1 
 
    NSString *astring01 = @"this is a String!";   
    NSString *astring02 = @"This is a String!";   
    BOOL result = [astring01 caseInsensitiveCompare:astring02] = = NSOrderedSame;       
     NSLog(@"result:%d",result);       
 
改变字符串的大小写  
 
    NSString *string1 = @"A String";   
    NSString *string2 = @"String";   
    NSLog(@"string1:%@",[string1 uppercaseString]);//大写  
    NSLog(@"string2:%@",[string2 lowercaseString]);//小写  
    NSLog(@"string2:%@",[string2 capitalizedString]);//首字母大小  
 
在串中搜索子串      
 
    NSString *string1 = @"This is a string";  
    NSString *string2 = @"string";  
    NSRange range = [string1 rangeOfString:string2];  
    int location = range.location;  
    int leight = range.length;  
    NSString *astring = [[NSString alloc] initWithString:[NSString stringWithFormat:@"Location:%i,Leight:%i",location,leight]];  
    NSLog(@"astring:%@",astring);  
    [astring release];  
 
替换字符串 
 
    NSString *astring01 = @"hello 中国";  
    NSString * new = [astring01 stringByReplacingOccurrencesOfString:@”中国” withString:@"北京"];    
    NSLog(new);    
 
分割字符串成数组 
 
    NSString *s = @"a b d e f";  
    NSArray *arr = [s componentsSeparatedByString:@" "];  
    NSLog(@"count = %d",[arr count]);  
 
字符串数组拼接成字符串 
 
    NSArray *pathArray = [NSArray arrayWithObjects:@"here",    
                               @"be", @"dragons", nil];    
         NSLog(@"%@",[pathArray componentsJoinedByString:@""]);    
 
抽取子串      
 
-substringToIndex: 从字符串的开头一直截取到指定的位置,但不包括该位置的字符 
 
    NSString *string1 = @"This is a string";  
    NSString *string2 = [string1 substringToIndex:3];  
    NSLog(@"string2:%@",string2);  
 
-substringFromIndex: 以指定位置开始(包括指定位置的字符),并包括之后的全部字符 
 
    NSString *string1 = @"This is a string";  
    NSString *string2 = [string1 substringFromIndex:3];  
    NSLog(@"string2:%@",string2);  
 
-substringWithRange: //按照所给出的位置,长度,任意地从字符串中截取子串 
 
    NSString *string1 = @"This is a string";  
    NSString *string2 = [string1 substringWithRange:NSMakeRange(0, 4)];  
    NSLog(@"string2:%@",string2);  
 
二、NSMutableString
 
给字符串分配容量
 
    //stringWithCapacity:  
    NSMutableString *String;  
    String = [NSMutableString stringWithCapacity:40];  
 
在已有字符串后面添加字符
 
    //appendString: and appendFormat:  
    NSMutableString *String1 = [[NSMutableString alloc] initWithString:@"This is a NSMutableString"];  
    //[String1 appendString:@", I will be adding some character"];  
    [String1 appendFormat:[NSString stringWithFormat:@", I will be adding some character"]];  
    NSLog(@"String1:%@",String1);  
    */  
 
在已有字符串中按照所给出范围和长度删除字符
 
    //deleteCharactersInRange:  
    NSMutableString *String1 = [[NSMutableString alloc] initWithString:@"This is a NSMutableString"];  
    [String1 deleteCharactersInRange:NSMakeRange(0, 5)];  
    NSLog(@"String1:%@",String1);  
 
在已有字符串后面在所指定的位置中插入给出的字符串
 
    //-insertString: atIndex:  
    NSMutableString *String1 = [[NSMutableString alloc] initWithString:@"This is a NSMutableString"];  
    [String1 insertString:@"Hi! " atIndex:0];  
    NSLog(@"String1:%@",String1);  
 
将已有的换成其它的字符串
 
    //-setString:  
    NSMutableString *String1 = [[NSMutableString alloc] initWithString:@"This is a NSMutableString"];  
    [String1 setString:@"Hello Word!"];  
    NSLog(@"String1:%@",String1);  
 
按照所给出的范围,和字符串替换的原有的字符
 
    //-setString:  
    NSMutableString *String1 = [[NSMutableString alloc] initWithString:@"This is a NSMutableString"];  
    [String1 replaceCharactersInRange:NSMakeRange(0, 4) withString:@"That"];  
    NSLog(@"String1:%@",String1);  
 
三、NSArray
 
创建数组
 
    NSArray *array = [[NSArray alloc] initWithObjects:   
    @"One",@"Two",@"Three",@"Four",nil];   
    self.dataArray = array;   
    [array release];   
    //- (unsigned) Count;数组所包含对象个数;   
    NSLog(@"self.dataArray cound:%d",[self.dataArray count]);   
    //获取指定索引处的对象  
    NSLog(@"self.dataArray cound 2:%@",[self.dataArray objectAtIndex:2]);   
 
从一个数组拷贝数据到另一数组
 
         //arrayWithArray:  
         //NSArray *array1 = [[NSArray alloc] init];  
         NSMutableArray *MutableArray = [[NSMutableArray alloc] init];  
         NSArray *array = [NSArray arrayWithObjects:  
                           @"a",@"b",@"c",nil];  
         NSLog(@"array:%@",array);  
         MutableArray = [NSMutableArray arrayWithArray:array];  
         NSLog(@"MutableArray:%@",MutableArray);  
         array1 = [NSArray arrayWithArray:array];  
         NSLog(@"array1:%@",array1);  
         //Copy  
         //id obj;  
         NSMutableArray *newArray = [[NSMutableArray alloc] init];  
         NSArray *oldArray = [NSArray arrayWithObjects:  
    @"a",@"b",@"c",@"d",@"e",@"f",@"g",@"h",nil];  
         NSLog(@"oldArray:%@",oldArray);  
         for(int i = 0; i < [oldArray count]; i++)  
         {          
             obj = [[oldArray objectAtIndex:i] copy];  
             [newArray addObject: obj];  
         }  
         //       
         NSLog(@"newArray:%@", newArray);  
         [newArray release];  
 
快速遍历数组
 
         //NSMutableArray *newArray = [[NSMutableArray alloc] init];  
         NSArray *oldArray = [NSArray arrayWithObjects:  
    @"a",@"b",@"c",@"d",@"e",@"f",@"g",@"h",nil];      
         NSLog(@"oldArray:%@",oldArray);  
         for(id obj in oldArray)  
         {  
             [newArray addObject: obj];  
         }  
         //       
         NSLog(@"newArray:%@", newArray);  
         [newArray release];      
     Copy and sort  
         //NSMutableArray *newArray = [[NSMutableArray alloc] init];  
         NSArray *oldArray = [NSArray arrayWithObjects:  
    @"b",@"a",@"e",@"d",@"c",@"f",@"h",@"g",nil];      
         NSLog(@"oldArray:%@",oldArray);  
         NSEnumerator *enumerator;  
         enumerator = [oldArray objectEnumerator];  
         id obj;  
         while(obj = [enumerator nextObject])  
         {  
             [newArray addObject: obj];  
         }  
         [newArray sortUsingSelector:@selector(compare:)];  
         NSLog(@"newArray:%@", newArray);  
     [newArray release];  
     NSMutableArray  
 
给数组分配容量
 
    //NSArray *array;  
    array = [NSMutableArray arrayWithCapacity:20];  
 
在数组末尾添加对象
 
    //- (void) addObject: (id) anObject;  
    //NSMutableArray *array = [NSMutableArray arrayWithObjects:  
    @"One",@"Two",@"Three",nil];  
    [array addObject:@"Four"];  
    NSLog(@"array:%@",array);  
 
删除数组中指定索引处对象
 
    //-(void) removeObjectAtIndex: (unsigned) index;      
    //NSMutableArray *array = [NSMutableArray arrayWithObjects:  
    @"One",@"Two",@"Three",nil];  
    [array removeObjectAtIndex:1];  
    NSLog(@"array:%@",array);  
 
数组枚举
 
从前向后
 
    //NSMutableArray *array = [NSMutableArray arrayWithObjects:  
    @"One",@"Two",@"Three",nil];  
    NSEnumerator *enumerator;  
    enumerator = [array objectEnumerator];  
    id thingie;  
    while (thingie = [enumerator nextObject]) {  
        NSLog(@"thingie:%@",thingie);  
    }  
 
从后向前
 
    NSMutableArray *array = [NSMutableArray arrayWithObjects:  
        @"One",@"Two",@"Three",nil];  
        NSEnumerator *enumerator;  
        enumerator = [array reverseObjectEnumerator];  
        id object;  
        while (object = [enumerator nextObject]) {  
            NSLog(@"object:%@",object);  
        }  
 
快速枚举
 
        //NSMutableArray *array = [NSMutableArray arrayWithObjects:  
        @"One",@"Two",@"Three",nil];  
        for(NSString *string in array)  
        {  
            NSLog(@"string:%@",string);  
        }  
    NSDictionary  
 
创建字典
 
    //- (id) initWithObjectsAndKeys;  
    ctionary *dictionary = [[NSDictionary alloc] initWithObjectsAndKeys:@"One",@"1",@"Two",@"2",@"Three",@"3",nil];  
    NSString *string = [dictionary objectForKey:@"One"];  
    NSLog(@"string:%@",string);  
    NSLog(@"dictionary:%@",dictionary);  
    [dictionary release];  
 
练习题:将文本“成绩单.text”内容加载到内存中并按规定的格式输出出来
 
NSMutableDictionary 
 
创建
 
    NSMutableDictionary *dictionary = [NSMutableDictionary dictionary];  
 
添加字典
 
    [dictionary setObject:@"One" forKey:@"1"];  
    [dictionary setObject:@"Two" forKey:@"2"];  
    [dictionary setObject:@"Three" forKey:@"3"];  
    [dictionary setObject:@"Four" forKey:@"4"];  
    NSLog(@"dictionary:%@",dictionary);  
 
删除指定的字典
 
    [dictionary removeObjectForKey:@"3"];  
    NSLog(@"dictionary:%@",dictionary);  
 
NSValue(对任何对象进行包装)
 
将NSRect放入NSArray中
 
    NSMutableArray *array = [[NSMutableArray alloc] init];  
    NSValue *value;  
    CGRect rect = CGRectMake(0, 0, 320, 480);      
    value = [NSValue valueWithBytes:&rect objCType:@encode(CGRect)];  
    [array addObject:value];  
    NSLog(@"array:%@",array);  
 
从Array中提取
 
    value = [array objectAtIndex:0];  
    [value getValue:&rect];  
    NSLog(@"value:%@",value);  
 
定义结构体并添加到NSArray里面
 
    typedef struct {  
    float real;  
    float imaginary;  
    } ImaginaryNumber;  
    ImaginaryNumber miNumber;  
    miNumber.real = 1.1;  
    miNumber.imaginary = 1.41;  
    NSValue *miValue = [NSValue value:miNumber  
    withObjCType:@encode(ImaginaryNumber)]; // encode using the type name  
    ImaginaryNumber miNumber2;  
    [miValue getValue:&miNumber2];  
 
四、宏定义#define讲解
 
NSNumber 
 
    + (NSNumber *)numberWithInt:(int)value;  
    + (NSNumber *)numberWithDouble:(double)value;  
    - (int)intValue;  
    - (double)doubleValue;  
 
NSNumber可以将基本数据类型包装起来,形成一个对象,这样就可以给其发送消息,装入NSArray中等等。
 
    NSNumber * intNumber=[NSNumber numberWithInt:100];  
    NSNumber *floatNumber=[NSNUmber numberWithFloat:100.00];  
    int i=[intNumber intValue];  
    if([intNumber isEqualToNumber:floatNumber]) ....  
 
NSNumber继承NSObject ,可以使用比较 compare: isEqual等消息
 
NSNull
 
IOS里面最小简单的类,里面只有一个方法+(NSNull*) null;
 
数学常用方法
 
数学常量:
 
    #define M_E         2.71828182845904523536028747135266250   // e 
    #define M_LOG2E     1.44269504088896340735992468100189214   // log 2e 
    #define M_LOG10E    0.434294481903251827651128918916605082  // log 10e 
    #define M_LN2       0.693147180559945309417232121458176568  // log e2 
    #define M_LN10      2.30258509299404568401799145468436421   // log e10 
    #define M_PI        3.14159265358979323846264338327950288   // pi 
    #define M_PI_2      1.57079632679489661923132169163975144   // pi/2 
    #define M_PI_4      0.785398163397448309615660845819875721  // pi/4 
    #define M_1_PI      0.318309886183790671537767526745028724  // 1/pi 
    #define M_2_PI      0.636619772367581343075535053490057448  // 2/pi 
    #define M_2_SQRTPI  1.12837916709551257389615890312154517   // 2/sqrt(pi) 
    #define M_SQRT2     1.41421356237309504880168872420969808   // sqrt(2) 
    #define M_SQRT1_2   0.707106781186547524400844362104849039  // 1/sqrt(2)  
 
常用函数:
 
指数运算
 
    NSLog(@"%.f", pow(3,2) ); //result 9 
    NSLog(@"%.f", pow(3,3) ); //result 27  
 
开平方运算(计算两点间的距离时用到)
 
    NSLog(@"%.f", sqrt(16) ); //result 4 
    NSLog(@"%.f", sqrt(81) ); //result 9  
 
上舍入
 
    NSLog(@"res: %.f", ceil(3.000000000001)); //result 4 
    NSLog(@"res: %.f", ceil(3.00)); //result 3  
 
下舍入
 
    NSLog(@"res: %.f", floor(3.000000000001)); //result 3 
    NSLog(@"res: %.f", floor(3.9999999)); //result 3  
 
四舍五入
 
    NSLog(@"res: %.f", round(3.5)); //result 4 
    NSLog(@"res: %.f", round(3.46)); //result 3 
    NSLog(@"res: %.f", round(-3.5)); //NB: this one returns -4  
 
最小值
 
    NSLog(@"res: %.f", fmin(5,10)); //result 5  
 
最大值
 
    NSLog(@"res: %.f", fmax(5,10)); //result 10  
 
绝对值
 
    NSLog(@"res: %.f", fabs(10)); //result 10 
    NSLog(@"res: %.f", fabs(-10)); //result 10  
 
NSDate
 
得到当前的日期
 
    NSDate *date = [NSDate date];   
 
日期之间比较可用以下方法
 
    - (BOOL)isEqualToDate:(NSDate *)otherDate;// 与otherDate比较,相同返回YES  
    - (NSDate *)earlierDate:(NSDate *)anotherDate;// 与anotherDate比较,返回较早的那个日期  
    - (NSDate *)laterDate:(NSDate *)anotherDate;//与anotherDate比较,返回较晚的那个日期  
 
将日期转换成字符串
 
    NSLog(@”date = %@”,[data description]);  
 
设置日期显示格式
 
    NSDateFormatter *formatter =[[[NSDateFormatter alloc] init] autorelease];   
     [formatter setTimeStyle:NSDateFormatterFullStyle]; //设置几种默认的显示效果 
     [formatter setDateFormat:@"yyyy-MM-dd HH:mm:ss a"];//设置自定义的显示效果  
     NSLog([formatter stringFromDate:date]);  
 
NSData
 
    NSData-> NSString   
    NSString *aString = [[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding];   
    NSString->NSData   
    NSString *aString = @"1234abcd";   
    NSData *aData = [aString dataUsingEncoding: NSUTF8StringEncoding];

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