轉：用法總結：NSNumber、NSString、NSDate、NSCalendarDate、NSData(待續)

NSNumber

+ (NSNumber *)numberWithInt:(int)value;

+ (NSNumber *)numberWithDouble:(double)value;

- (int)intValue;

- (double)doubleValue;

NSNumber能夠將基本數據類型包裝起來，造成一個對象，這樣就能夠給其發送消息，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 ，可使用比較 compare： isEqual等消息

 

NSString

一個NSString對象能夠存儲一段Unicode字符。在cocoa中，全部和字符、字符串相關的處理都是使用NSString來完成。

NSObject -> NSString     // NSString繼承自NSObject

+(id) stringWithContentsOfFile:path encoding:enc error:err;

+(id) stringWithContentsOfURL:url encoding:enc error:err;

+(id) stringWithString:nsstring;   //建立一個新的字符串，並將其設置爲nsstring

-(id)initWithFormat:(NSString *)format, ...  ;

-(id)initWithString:nsstring;     //將分配的字符串設置爲nsstring

- (BOOL)isEqualToString:(NSString *)string;

- (BOOL)hasPrefix:(NSString *)string;

- (int)intValue;

- (double)doubleValue;

 

- (NSString *)stringByAppendingString:(NSString *)string;  // 給一個字符串附加一個字符串string。

- (NSString *)stringByAppendingFormat:(NSString *)string;

- (NSString *)stringByDeletingPathComponent;

 

----- 建立字符串的方法-----

//一、建立常量字符串

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

//二、先建立一個空的字符串，而後賦值；

//    alloc和init組合則適合在函數之間傳遞參數，用完以後須要手工release

    NSString *astring = [[NSString alloc] init];
    astring = @"This is a String!";
    NSLog(@"astring:%@",astring);
    [astring release];

//三、在以上方法中，提高速度:initWithString方法

    NSString *astring = [[NSString alloc] initWithString:@"This is a String!"];
    NSLog(@"astring:%@",astring);
    [astring release];
//四、建立臨時字符串

    NSString *astring;
    astring = [NSString stringWithCString:"This is a temporary string"];
    NSLog(@"astring:%@",astring);

// OR

    NSString *  scriptString = [NSString stringWithString:@" tell application \"Mail\"\r"];

//五、建立格式化字符串:佔位符（由一個%加一個字符組成）

    int i = 1;
    int j = 2;
    NSString *astring = [[NSString alloc] initWithString:[NSString stringWithFormat:@"%d.This is %i string!",i,j]];
    NSLog(@"astring:%@",astring);
    [astring release];

-----從文件讀取字符串-----
    NSString *path = @"astring.text";
    NSString *astring = [[NSString alloc] initWithContentsOfFile:path];
    NSLog(@"astring:%@",astring);
    [astring release];

-----寫字符串到文件----    
    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-----
//一、用C比較:strcmp函數
    char string1[] = "string!";
    char string2[] = "string!";
    if(strcmp(string1, string2) = = 0)
    {
        NSLog(@"1");
    }
 //二、isEqualToString方法   
    NSString *astring01 = @"This is a String!";
    NSString *astring02 = @"This is a String!";
    BOOL result = [astring01 isEqualToString:astring02];
    NSLog(@"result:%d",result);
//三、compare方法(comparer返回的三種值：NSOrderedSame，NSOrderedAscending，NSOrderedDescending)   
    NSString *astring01 = @"This is a String!";
    NSString *astring02 = @"This is a String!";   
    BOOL result = [astring01 compare:astring02] = = NSOrderedSame;   //NSOrderedSame 判斷二者內容是否相同
    NSLog(@"result:%d",result);   

    NSString *astring01 = @"This is a String!";
    NSString *astring02 = @"this is a String!";
    BOOL result = [astring01 compare:astring02] = = NSOrderedAscending;   
    NSLog(@"result:%d",result);
    //NSOrderedAscending 判斷兩對象值的大小(按字母順序進行比較，astring02大於astring01爲真)

    NSString *astring01 = @"this is a String!";
    NSString *astring02 = @"This is a String!";
    BOOL result = [astring01 compare:astring02] = = NSOrderedDescending;   
    NSLog(@"result:%d",result);     
    //NSOrderedDescending 判斷兩對象值的大小(按字母順序進行比較，astring02小於astring01爲真)
 //四、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);     
    //NSOrderedDescending判斷兩對象值的大小(按字母順序進行比較，astring02小於astring01爲真)
//五、不考慮大小寫比較字符串2
    NSString *astring01 = @"this is a String!";
    NSString *astring02 = @"This is a String!";
    BOOL result = [astring01 compare:astring02
                            options:NSCaseInsensitiveSearch | NSNumericSearch] = = NSOrderedSame;   
    NSLog(@"result:%d",result);     
    //NSCaseInsensitiveSearch:不區分大小寫比較 NSLiteralSearch:進行徹底比較，區分大小寫 NSNumericSearch:比較字符串的字符個數，而不是字符值。

-----改變字符串的大小寫-----
    NSString *string1 = @"A String";
    NSString *string2 = @"String";
    NSLog(@"string1:%@",[string1 uppercaseString]);//uppercaseString返回轉換爲大寫的字符串
    NSLog(@"string2:%@",[string2 lowercaseString]);//lowercaseString返回轉換爲小寫的字符串
    NSLog(@"string2:%@",[string2 capitalizedString]);//capitalizedString返回每一個單詞首字母大寫的字符串

-----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];

-----抽取子串 -----     

//一、-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);

//二、-substringFromIndex: 以指定位置開始（包括指定位置的字符），幷包括以後的所有字符
    NSString *string1 = @"This is a string";
    NSString *string2 = [string1 substringFromIndex:3];
    NSLog(@"string2:%@",string2);

//三、-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);

//四、快速枚舉
    for(NSString *filename in direnum)    {
        if([[filename pathExtension] isEqualToString:@"jpg"]){
            [files addObject:filename];
        }
    }
    NSLog(@"files:%@",files);

//五、枚舉
    NSEnumerator *filenum;
    filenum = [files objectEnumerator];
    while (filename = [filenum nextObject]) {
        NSLog(@"filename:%@",filename);
    }

@"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];

-----切分數組-----
//一、從字符串分割到數組－ componentsSeparatedByString:
    NSString *string = [[NSString alloc] initWithString:@"One,Two,Three,Four"];
    NSLog(@"string:%@",string);   
    NSArray *array = [string componentsSeparatedByString:@","];
    NSLog(@"array:%@",array);
    [string release];

//二、從數組合並元素到字符串- componentsJoinedByString:
    NSArray *array = [[NSArray alloc] initWithObjects:@"One",@"Two",@"Three",@"Four",nil];
    NSString *string = [array componentsJoinedByString:@","];
    NSLog(@"string:%@",string);

-----從目錄搜索擴展名爲jpg的文件-----
//NSFileManager *fileManager = [NSFileManager defaultManager];
    NSString *home;
    home = @"../Users/";
    NSDirectoryEnumerator *direnum;
    direnum = [fileManager enumeratorAtPath: home];
    NSMutableArray *files = [[NSMutableArray alloc] init];
//枚舉
    NSString *filename;
    while (filename = [direnum nextObject]) {
        if([[filename pathExtension] hasSuffix:@"jpg"]){
            [files addObject:filename];
        }
    }
//擴展路徑 
    NSString *Path = @"~/NSData.txt";
    NSString *absolutePath = [Path stringByExpandingTildeInPath];
    NSLog(@"absolutePath:%@",absolutePath);
    NSLog(@"Path:%@",[absolutePath stringByAbbreviatingWithTildeInPath]);
//文件擴展名
    NSString *Path = @"~/NSData.txt";
    NSLog(@"Extension:%@",[Path pathExtension]);

-----查找與替換-----

- (NSString *)stringByReplacingCharactersInRange:(NSRange)range withString:(NSString *)replacement

- (NSString *)stringByReplacingOccurrencesOfString:(NSString *)target withString:(NSString *)replacement

NSMutableString(可修改的字符串)

NSObject -> NSString -> NSMutableString 

Common NSMutableString methods
+ (id)string;
- (void)appendString:(NSString *)string;
- (void)appendFormat:(NSString *)format, ...;

----- 給字符串分配容量-----
    //stringWithCapacity:
    NSMutableString *String;
    String = [NSMutableString stringWithCapacity:40];

-----在已有字符串後面添加字符-----   

    //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範圍刪除字符----   
     //deleteCharactersInRange:
     NSMutableString *String1 = [[NSMutableString alloc] initWithString:@"This is a NSMutableString"];
     [String1 deleteCharactersInRange:NSMakeRange(0, 5)];    // 刪除指定範圍（location=0，length=5）的字符串
     NSLog(@"String1:%@",String1);
----在已有字符串後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);
    [String1 insertString:@"and StringEnd", atIndex:[String1 length]];  //  在可變字符串的最後插入
----將已有的空符串換成其它的字符串-----
    //-setString:
    NSMutableString *String1 = [[NSMutableString alloc] initWithString:@"This is a NSMutableString"];
    [String1 setString:@"Hello Word!"];
    NSLog(@"String1:%@",String1);

----查找-----
   NSRange subRange = [String1 rangeOfString:@"is a"];   // 若是沒查找到，則 （subRange.location == NSNotFound）爲真。

----按照所給出的範圍替換的原有的字符-----
    //-setString:
    NSMutableString *String1 = [[NSMutableString alloc] initWithString:@"This is a NSMutableString"];
    [String1 replaceCharactersInRange:NSMakeRange(0, 4) withString:@"That"];     // 用於NSMutableString
    NSLog(@"String1:%@",String1);

---- 在給定的範圍內查找並替換-----
- (NSUInteger)replaceOccurrencesOfString:(NSString *)target withString:(NSString *)replacement options:(NSStringCompareOptions)opts range:(NSRange)searchRange

----判斷字符串內是否還包含別的字符串(前綴，後綴)-----
//01： 檢查字符串是否以另外一個字符串開頭- (BOOL) hasPrefix: (NSString *) aString;
    NSString *String1 = @"NSStringInformation.txt";
    [String1 hasPrefix:@"NSString"] = = 1 ?  NSLog(@"YES") : NSLog(@"NO");
    [String1 hasSuffix:@".txt"] = = 1 ?  NSLog(@"YES") : NSLog(@"NO");

//02： 查找字符串某處是否包含給定的字符串 - (NSRange) rangeOfString: (NSString *) aString，這一點前面在串中搜索子串用到過

NSRange subRange;
subRange = [string1 rangeOfString:@"string A"];  //查找字符串string1中是否包含「string A」。返回NSRange類型。
if(subRange.location == NSNotFound)
     NSLog(@"String not found ");
else  NSLog(@"string is at index %lu, length is %lu", subRange.location, subRange.length);

NSDate

 

NSCalendarDate

NSCalendarDate對象包含了日期和時間、時區以及一個帶有格式的字符串，它從NSDate繼承而來。

NSCalendarDate對象是immutable的，一旦被建立，沒法修改其中的時間和日期，固然能夠修改那個帶格式的字符串和時區。

如下是經常使用方法：

+(id)calendarDate;  //建立當前日期和時間以及默認格式的NSCalendarDate對象，時區爲機器設置好的時區。

 

 

+(id)dateWithYear:(int)year

    month:(unsigned)month

      day:(unsigned)day 

     hour:(unsigned)hour

   minute:(unsigned)minute

   second:(unsigned)second 

 timeZone:(NSTimeZone  *)aTimeZone 

 

 

-(int)dayOfCommonEra;  //獲得從公元1年算起，有多少天

-(int)dayOfMonth;          //返回是月的第幾天（1-31）

-(int)dayOfWeek;          //返回是周的第幾天 （0-6）

-(int)dayOfYear;          //返回是年的第幾天（1-366）

-(int)hourOfDay;          // 返回是日的第幾個小時（0-23）

-(void)setCalendarFormate:(NSString *)format 

--------建立NSCalendarDate對象--------

NSCalendarDate *now;

now = [NSCalendarDate calendarDate];

 

 

NSTimeZone *pacific = [NSTimeZone timeZoneWithName:@"PST"];

NSCalendarDate *hotTime = [NSCalendarDate dateWithYear:2011 month:2 day:3 hour:14 minute:0 second:0 timeZone:pacific];

 

 

NSData

使用文件時，須要頻繁地將數據讀入一個臨時存儲區，它一般成爲緩衝區。

NSData類提供了一種簡單的方式，它用來設置緩衝區、將文件的內容讀入緩衝區，或將緩衝區的內容寫到一個文件。

對於32位應用程序，NSDATA緩存區最多能夠存儲2GB的數據。

咱們既可定義不變緩衝區（NSData類），也可定義可變的緩衝區（NSMutableData類）。

下面代碼展現瞭如何將文件的內容讀入內存緩衝區，而後再將緩衝區的內容寫入到另外一個文件中。

NSData *fileData; NSFileManager *fileManager = [[NSFileManager alloc]init]; fileData = [fileManager contentsAtPath:path]; [fileManager createFileAtPath:path2 contents:fileData attributes:nil]; //採用默認的屬性值

類型轉換 NSData -> NSString：

NSString *strData = [[NSString alloc]initWithData:fileData encoding:NSASCIIStringEncoding];

類型轉換 NSString -> NSData：

NSData *fileData2 = [strData dataUsingEncoding:NSUTF8StringEncoding];

NSMutableData