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NSString 和NSArray用法大全详解

qq123 2018年06月23日 手机开发 358 0
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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 = [email protected],[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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