用法總結：NSNumber、NSString、NSData

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

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

- (int)intValue;

- (double)doubleValue;

NSNumber可以將基本資料型別包裝起來，形成一個物件，這樣就可以給其傳送訊息，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等訊息

//3、在以上方法中，提升速度:initWithString方法

    NSString*astring = [[NSString alloc] initWithString:@"Thisis a String!"];
   NSLog(@"astring:%@",astring);
    [astring release];
//4、建立臨時字串

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

// OR

//5、建立格式化字串:佔位符（由一個%加一個字元組成）

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

-----從檔案讀取字串-----
    NSString*path = @"astring.text";
    NSString *astring =[[NSString alloc] initWithContentsOfFile:path];
   NSLog(@"astring:%@",astring);
    [astring release];

-----寫字串到檔案----    
    NSString*astring = [[NSString alloc] initWithString:@"This is aString!"];
   NSLog(@"astring:%@",astring);
    NSString *path =@"astring.text";   
   [astring writeToFile: path atomically:YES];
    [astringrelease];   
-----比較兩個字串-----
//1、用C比較:strcmp函式
    charstring1[] = "string!";
    char string2[] ="string!";
    if(strcmp(string1, string2) = =0)
    {
       NSLog(@"1");
    }
 //2、isEqualToString方法  
    NSString *astring01 = @"Thisis a String!";
    NSString *astring02 = @"Thisis a String!";
    BOOL result =[astring01 isEqualToString:astring02];
   NSLog(@"result:%d",result);
//3、compare方法(comparer返回的三種值：NSOrderedSame，NSOrderedAscending，NSOrderedDescending)  
    NSString *astring01 = @"Thisis a String!";
    NSString *astring02 = @"Thisis a String!";   
    BOOL result =[astring01 compare:astring02] == NSOrderedSame;   //NSOrderedSame判斷兩者內容是否相同
   NSLog(@"result:%d",result);   

    NSString*astring01 = @"This is a String!";
    NSString *astring02 = @"thisis a String!";
    BOOL result =[astring01 compare:astring02] == NSOrderedAscending;  
   NSLog(@"result:%d",result);
    //NSOrderedAscending判斷兩物件值的大小(按字母順序進行比較，astring02大於astring01為真)

   NSString *astring01 = @"this is aString!";
    NSString *astring02 = @"Thisis a String!";
    BOOL result =[astring01 compare:astring02] == NSOrderedDescending;  
   NSLog(@"result:%d",result);    
    //NSOrderedDescending判斷兩物件值的大小(按字母順序進行比較，astring02小於astring01為真)
 //4、不考慮大小寫比較字串1
    NSString *astring01 = @"thisis a String!";
    NSString *astring02 = @"Thisis a String!";
    BOOL result =[astring01 caseInsensitiveCompare:astring02] == NSOrderedSame;   
   NSLog(@"result:%d",result);    
   //NSOrderedDescending判斷兩物件值的大小(按字母順序進行比較，astring02小於astring01為真)
//5、不考慮大小寫比較字串2
    NSString *astring01 = @"thisis a String!";
    NSString *astring02 = @"Thisis a String!";
    BOOL result = [astring01compare:astring02
                    options:NSCaseInsensitiveSearch | NSNumericSearch] = =NSOrderedSame;   
   NSLog(@"result:%d",result);     
   //NSCaseInsensitiveSearch:不區分大小寫比較NSLiteralSearch:進行完全比較，區分大小寫 NSNumericSearch:比較字串的字元個數，而不是字元值。

-----改變字串的大小寫-----
    NSString*string1 = @"A String";
    NSString *string2 =@"String";
    NSLog(@"string1:%@",[string1uppercaseString]);//uppercaseString返回轉換為大寫的字串
   NSLog(@"string2:%@",[string2 lowercaseString]);//lowercaseString返回轉換為小寫的字串
   NSLog(@"string2:%@",[string2 capitalizedString]);//capitalizedString返回每個單詞首字母大寫的字串

-----在串中搜尋子串 -----        

   NSString *string1 = @"This is a string";
    NSString *string2 =@"string";
    NSRange range = [string1rangeOfString:string2];
    int location =range.location;
    int leight =range.length;
    NSString *astring =[[NSString alloc] initWithString:[NSStringstringWithFormat:@"Location:%i,Leight:%i",location,leight]];
   NSLog(@"astring:%@",astring);
    [astring release];

-----抽取子串 -----     

//1、-substringToIndex: 從字串的開頭一直擷取到指定的位置，但不包括該位置的字元
    NSString *string1 = @"This isa string";
    NSString *string2 =[string1 substringToIndex:3]; 
   NSLog(@"string2:%@",string2);

//2、-substringFromIndex: 以指定位置開始（包括指定位置的字元），幷包括之後的全部字元
    NSString *string1 = @"This isa string";
    NSString *string2 =[string1 substringFromIndex:3];
   NSLog(@"string2:%@",string2);

//3、-substringWithRange: //按照所給出的位置，長度，任意地從字串中擷取子串
    NSString *string1 = @"This isa string";
    NSString *string2 =[string1 substringWithRange:NSMakeRange(0,4)];
   NSLog(@"string2:%@",string2);

//4、快速列舉
    for(NSString*filename indirenum)   {
       if([[filename pathExtension] isEqualToString:@"jpg"]){
            [filesaddObject:filename];
       }
   }
  NSLog(@"files:%@",files);

//5、列舉
    NSEnumerator *filenum;
    filenum = [filesobjectEnumerator];
    while (filename = [filenumnextObject]) {
       NSLog(@"filename:%@",filename);
    }

@"b",@"a",@"e",@"d",@"c",@"f",@"h",@"g",nil];  
   NSLog(@"oldArray:%@",oldArray);
    NSEnumerator*enumerator;
    enumerator = [oldArrayobjectEnumerator];
    id obj;
    while(obj = [enumeratornextObject])   {
       [newArrayaddObject: obj];
    }
    [newArraysortUsingSelector:@selector(compare:)];
    NSLog(@"newArray:%@",newArray);
    [newArrayrelease];

-----切分陣列-----
//1、從字串分割到陣列－componentsSeparatedByString:
    NSString *string = [[NSStringalloc] initWithString:@"One,Two,Three,Four"];
   NSLog(@"string:%@",string);  
    NSArray *array= [string componentsSeparatedByString:@","];
   NSLog(@"array:%@",array);
    [stringrelease];

//2、從陣列合並元素到字串-componentsJoinedByString:
    NSArray *array = [[NSArrayalloc] initWithObjects:@"One",@"Two",@"Three",@"Four",nil];
    NSString *string = [arraycomponentsJoinedByString:@","];
   NSLog(@"string:%@",string);

-----從目錄搜尋副檔名為jpg的檔案-----
//NSFileManager *fileManager= [NSFileManager defaultManager];
    NSString *home;
    home = @"../Users/";
    NSDirectoryEnumerator*direnum;
    direnum = [fileManagerenumeratorAtPath: home];
    NSMutableArray*files = [[NSMutableArray alloc]init];
//列舉
    NSString *filename;
    while (filename = [direnumnextObject]) {
       if([[filenamepathExtension] hasSuffix:@"jpg"]){
          [filesaddObject:filename];
       }
   }
//擴充套件路徑 
   NSString *Path = @"~/NSData.txt";
    NSString *absolutePath =[Path stringByExpandingTildeInPath];
   NSLog(@"absolutePath:%@",absolutePath);
   NSLog(@"Path:%@",[absolutePathstringByAbbreviatingWithTildeInPath]);
//副檔名
    NSString *Path =@"~/NSData.txt";
    NSLog(@"Extension:%@",[PathpathExtension]);

-----查詢與替換-----

- (NSString *)stringByReplacingCharactersInRange:(NSRange)rangewithString:(NSString *)replacement

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

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

-----在已有字串後面新增字元-----   

    //appendString:and appendFormat:
    NSMutableString*String1 = [[NSMutableString alloc] initWithString:@"This is aNSMutableString"];
   //[String1 appendString:@", I will be addingsome character"];
   [String1 appendFormat:[NSStringstringWithFormat:@", I will be adding some character"]];
   NSLog(@"String1:%@",String1);
----- 在已有字串中按照所給出範圍刪除字元----   
     //deleteCharactersInRange:
    NSMutableString*String1 = [[NSMutableString alloc] initWithString:@"This is aNSMutableString"];
    [String1 deleteCharactersInRange:NSMakeRange(0,5)];   // 刪除指定範圍（location=0，length=5）的字串
    NSLog(@"String1:%@",String1);
----在已有字串後面在所指定的位置中插入給出的字串-----
   //-insertString: atIndex:
    NSMutableString *String1 =[[NSMutableString alloc] initWithString:@"This is aNSMutableString"];
   [String1 insertString:@"Hi! "atIndex:0];
   NSLog(@"String1:%@",String1);
    [String1insertString:@"and StringEnd", atIndex:[String1length]];  // 在可變字串的最後插入
----將已有的空符串換成其它的字串-----
   //-setString:
    NSMutableString *String1 =[[NSMutableString alloc] initWithString:@"This is aNSMutableString"];
   [String1 setString:@"Hello Word!"];
   NSLog(@"String1:%@",String1);

----查詢-----
   NSRange subRange =[String1 rangeOfString:@"isa"];   // 如果沒查詢到，則（subRange.location == NSNotFound）為真。

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

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

----判斷字串內是否還包含別的字串(字首，字尾)-----
//01： 檢查字串是否以另一個字串開頭- (BOOL) hasPrefix: (NSString *)aString;
    NSString *String1 =@"NSStringInformation.txt";
    [String1hasPrefix:@"NSString"] = = 1?  NSLog(@"YES") :NSLog(@"NO");
    [String1 hasSuffix:@".txt"] == 1 ?  NSLog(@"YES") :NSLog(@"NO");

//02： 查詢字串某處是否包含給定的字串 -(NSRange) rangeOfString: (NSString *)aString，這一點前面在串中搜尋子串用到過

NSRange subRange;
subRange = [string1 rangeOfString:@"stringA"];  //查詢字串string1中是否包含“stringA”。返回NSRange型別。
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物件包含了日期和時間、時區以及一個帶有格式的字串，它從NSDate繼承而來。

NSCalendarDate物件是immutable的，一旦被建立，無法修改其中的時間和日期，當然可以修改那個帶格式的字串和時區。

以下是常用方法：

+(id)calendarDate; //建立當前日期和時間以及預設格式的NSCalendarDate物件，時區為機器設定好的時區。

 

 

+(id)dateWithYear:(int)year

   month:(unsigned)month

     day:(unsigned)day 

    hour:(unsigned)hour

   minute:(unsigned)minute

   second:(unsigned)second 

 timeZone:(NSTimeZone  *)aTimeZone 

 

 

-(int)dayOfCommonEra; //得到從公元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物件--------

NSCalendarDate*now;

now = [NSCalendarDatecalendarDate];

 

 

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

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

 

 

NSData

使用檔案時，需要頻繁地將資料讀入一個臨時儲存區，它通常成為緩衝區。

NSData類提供了一種簡單的方式，它用來設定緩衝區、將檔案的內容讀入緩衝區，或將緩衝區的內容寫到一個檔案。

對於32位應用程式，NSDATA快取區最多可以儲存2GB的資料。

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

下面程式碼展示瞭如何將檔案的內容讀入記憶體緩衝區，然後再將緩衝區的內容寫入到另一個檔案中。

<span style="color:#66066;">NSData</span><span> </span><span style="color:#66660;">*</span><span>fileData</span><span style="color:#66660;">;</span>
<span style="color:#66066;">NSFileManager</span><span> </span><span style="color:#66660;">*</span><span>fileManager </span><span style="color:#66660;">=</span><span> </span><span style="color:#66660;">[[</span><span style="color:#66066;">NSFileManager</span><span> alloc</span><span style="color:#66660;">]</span><span>init</span><span style="color:#66660;">];</span>
<span>fileData </span><span style="color:#66660;">=</span><span> </span><span style="color:#66660;">[</span><span>fileManager contentsAtPath</span><span style="color:#66660;">:</span><span>path</span><span style="color:#66660;">];</span><span>  </span>
<span style="color:#66660;">[</span><span>fileManager createFileAtPath</span><span style="color:#66660;">:</span><span>path2 contents</span><span style="color:#66660;">:</span><span>fileData attributes</span><span style="color:#66660;">:</span><span style="color:#0088;">nil</span><span style="color:#66660;">];</span><span>   </span><span style="color:#8800;">//採用預設的屬性值</span>

型別轉換 NSData -> NSString：

NSString *strData =[[NSString alloc]initWithData:fileDataencoding:NSASCIIStringEncoding];

型別轉換 NSString-> NSData：

NSData *fileData2 = [strDatadataUsingEncoding:NSUTF8StringEncoding];

NSMutableData