NSString 和NSArray用法大全

b77m 9年前發布 | 1K 次閱讀 Objective-C IOS
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一、NSString
創建字符串。

NSString *astring = @"This is a String!";  


創建空字符串，給予賦值。

NSString *astring = [[NSString alloc] init];  

astring = @"This is a String!";  

NSLog(@"astring:%@",astring);  

string release];  


使用變量初始化

NSString *name = @"Ivan!";  
   NSString *astring = [[NSString stringWithFormat:@”My name is %@!”,name]];  
   NSLog(@"astring:%@",astring);  


判斷是否包含某字符串
檢查字符串是否以另一個字符串開頭

- (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;  


從文件讀取字符串:

initWithContentsOfFile方法     
     NSString *path = @"astring.text";  
     NSString *astring = [[NSString alloc] initWithContentsOfFile:path];  
     NSLog(@"astring:%@",astring);  
     [astring release];  


寫字符串到文件: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];      


比較兩個字符串
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返回的三種值)

NSString *astring01 = @"This is a String!";  
     NSString *astring02 = @"This is a String!";      
     BOOL result = [astring01 compare:astring02] = = NSOrderedSame;      
     NSLog(@"result:%d",result);      


NSOrderedSame判斷兩者內容是否相同

NSString *astring01 = @"This is a String!";  
     NSString *astring02 = @"this is a String!";  
     BOOL result = [astring01 compare:astring02] = = NSOrderedAscending;      
     NSLog(@"result:%d",result);  


不考慮大小寫比較字符串1

NSString *astring01 = @"this is a String!";   
NSString *astring02 = @"This is a String!";   
BOOL result = [astring01 caseInsensitiveCompare:astring02] = = NSOrderedSame;       
 NSLog(@"result:%d",result);       


改變字符串的大小寫

NSString *string1 = @"A String";   
NSString *string2 = @"String";   
NSLog(@"string1:%@",[string1 uppercaseString]);//大寫  
NSLog(@"string2:%@",[string2 lowercaseString]);//小寫  
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];  


替換字符串

NSString *astring01 = @"hello 中國";  
NSString * new = [astring01 stringByReplacingOccurrencesOfString:@”中國” withString:@"北京"];    
NSLog(new);    


分割字符串成數組

NSString *s = @"a b d e f";  
NSArray *arr = [s componentsSeparatedByString:@" "];  
NSLog(@"count = %d",[arr count]);  


字符串數組拼接成字符串

NSArray *pathArray = [NSArray arrayWithObjects:@"here",    
                           @"be", @"dragons", nil];    
     NSLog(@"%@",[pathArray componentsJoinedByString:@""]);    


抽取子串
-substringToIndex: 從字符串的開頭一直截取到指定的位置，但不包括該位置的字符

NSString *string1 = @"This is a string";  
NSString *string2 = [string1 substringToIndex:3];  
NSLog(@"string2:%@",string2);  


-substringFromIndex: 以指定位置開始（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: //按照所給出的位置，長度，任意地從字符串中截取子串

NSString *string1 = @"This is a string";  
NSString *string2 = [string1 substringWithRange:NSMakeRange(0, 4)];  
NSLog(@"string2:%@",string2);  


二、NSMutableString
給字符串分配容量

//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給出范圍和長度刪除字符

//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給出的字符串

//-insertString: atIndex:  
NSMutableString *String1 = [[NSMutableString alloc] initWithString:@"This is a NSMutableString"];  
[String1 insertString:@"Hi! " atIndex:0];  
NSLog(@"String1:%@",String1);  


將已有的換成其它的字符串

//-setString:  
NSMutableString *String1 = [[NSMutableString alloc] initWithString:@"This is a NSMutableString"];  
[String1 setString:@"Hello Word!"];  
NSLog(@"String1:%@",String1);  


按照所給出的范圍，和字符串替換的原有的字符

//-setString:  
NSMutableString *String1 = [[NSMutableString alloc] initWithString:@"This is a NSMutableString"];  
[String1 replaceCharactersInRange:NSMakeRange(0, 4) withString:@"That"];  
NSLog(@"String1:%@",String1);  


三、NSArray
創建數組

NSArray *array = [[NSArray alloc] initWithObjects:   
@"One",@"Two",@"Three",@"Four",nil];   
self.dataArray = array;   
[array release];   
//- (unsigned) Count;數組所包含對象個數；   
NSLog(@"self.dataArray cound:%d",[self.dataArray count]);   
//獲取指定索引處的對象  
NSLog(@"self.dataArray cound 2:%@",[self.dataArray objectAtIndex:2]);   


從一個數組拷貝數據到另一數組

     //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];  


快速遍歷數組

     //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  


給數組分配容量

//NSArray *array;  
array = [NSMutableArray arrayWithCapacity:20];  


在數組末尾添加對象

//- (void) addObject: (id) anObject;  
//NSMutableArray *array = [NSMutableArray arrayWithObjects:  
@"One",@"Two",@"Three",nil];  
[array addObject:@"Four"];  
NSLog(@"array:%@",array);  


刪除數組中指定索引處對象

//-(void) removeObjectAtIndex: (unsigned) index;      
//NSMutableArray *array = [NSMutableArray arrayWithObjects:  
@"One",@"Two",@"Three",nil];  
[array removeObjectAtIndex:1];  
NSLog(@"array:%@",array);  


數組枚舉
從前向后

//NSMutableArray *array = [NSMutableArray arrayWithObjects:  
@"One",@"Two",@"Three",nil];  
NSEnumerator *enumerator;  
enumerator = [array objectEnumerator];  
id thingie;  
while (thingie = [enumerator nextObject]) {  
    NSLog(@"thingie:%@",thingie);  
}  


從后向前

NSMutableArray *array = [NSMutableArray arrayWithObjects:  
    @"One",@"Two",@"Three",nil];  
    NSEnumerator *enumerator;  
    enumerator = [array reverseObjectEnumerator];  
    id object;  
    while (object = [enumerator nextObject]) {  
        NSLog(@"object:%@",object);  
    }  


快速枚舉

    //NSMutableArray *array = [NSMutableArray arrayWithObjects:  
    @"One",@"Two",@"Three",nil];  
    for(NSString *string in array)  
    {  
        NSLog(@"string:%@",string);  
    }  
NSDictionary  


創建字典

//- (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];  


練習題：將文本“成績單.text”內容加載到內存中并按規定的格式輸出出來
NSMutableDictionary
創建

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);  


刪除指定的字典

[dictionary removeObjectForKey:@"3"];  
NSLog(@"dictionary:%@",dictionary);  


NSValue（對任何對象進行包裝）
將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);  


從Array中提取

value = [array objectAtIndex:0];  
[value getValue:&rect];  
NSLog(@"value:%@",value);  


定義結構體并添加到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、宏定義#define講解
NSNumber

+ (NSNumber *)numberWithInt:(int)value;  
+ (NSNumber *)numberWithDouble:(double)value;  
- (int)intValue;  
- (double)doubleValue;  


NSNumber可以將基本數據類型包裝起來，形成一個對象，這樣就可以給其發送消息，裝入NSArray中等等。

NSNumber * intNumber=[NSNumber numberWithInt：100]；  
NSNumber *floatNumber=[NSNUmber numberWithFloat:100.00];  
int i=[intNumber intValue]；  
if([intNumber isEqualToNumber:floatNumber]) ....  


NSNumber繼承NSObject ，可以使用比較 compare： isEqual等消息
NSNull
IOS里面最小簡單的類，里面只有一個方法+(NSNull*) null;
數學常用方法
數學常量：

#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)  


常用函數：
指數運算

NSLog(@"%.f", pow(3,2) ); //result 9 
NSLog(@"%.f", pow(3,3) ); //result 27  


開平方運算（計算兩點間的距離時用到）

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  


絕對值

NSLog(@"res: %.f", fabs(10)); //result 10 
NSLog(@"res: %.f", fabs(-10)); //result 10  


NSDate
得到當前的日期

NSDate *date = [NSDate date];   


日期之間比較可用以下方法

- (BOOL)isEqualToDate:(NSDate *)otherDate;// 與otherDate比較，相同返回YES  
- (NSDate *)earlierDate:(NSDate *)anotherDate;// 與anotherDate比較，返回較早的那個日期  
- (NSDate *)laterDate:(NSDate *)anotherDate;//與anotherDate比較，返回較晚的那個日期  


將日期轉換成字符串

NSLog(@”date = %@”,[data description]);  


設置日期顯示格式

NSDateFormatter *formatter =[[[NSDateFormatter alloc] init] autorelease];   
 [formatter setTimeStyle:NSDateFormatterFullStyle]; //設置幾種默認的顯示效果 
 [formatter setDateFormat:@"yyyy-MM-dd HH:mm:ss a"];//設置自定義的顯示效果  
 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];</pre>
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Objective-C IOS
NSString 和NSArray用法大全

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