用法：NSNumber、NSString、NSDate、NSCalendarDate、NSData

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

NSString

一個NSString對象可以存儲一段Unicode字符。在cocoa中，所有和字符、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; //創建一個新的字符串，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;

-----創建字符串的方法-----

//1、創建常量字符串

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

//2、先創建一個空的字符串，然後賦值；

// alloc和init組合則適合在函數之間傳遞參數，用完之後需要手工release

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

//3、在以上方法中，提升速度:initWithString方法

NSString *astring = [[NSString alloc] initWithString:@"This is a String!"];
NSLog(@"astring:%@",astring);
[astring release];
//4、創建臨時字符串

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

// OR

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

//5、創建格式化字符串: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-----
//1、用C比較:strcmp函數
    char string1[] = "string!";
char string2[] = "string!";
if(strcmp(string1, string2) = = 0)
{
      NSLog(@"1");
}
//2、isEqualToString方法
NSString *astring01 = @"This is a String!";
NSString *astring02 = @"This is 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 = @"This is a String!";
NSString *astring02 = @"This is a String!";
BOOL result = [astring01 compare:astring02] = = NSOrderedSame;   //NSOrderedSame 判斷兩者是否相同
    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)
//4、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)
//5、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:進行完全比較，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 -----

//1、-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);

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

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

//4、快速枚舉
    for(NSString *filename in direnum)    {
        if([[filename pathExtension] isEqualToString:@"jpg"]){
            [files addObject:filename];
        }
    }
NSLog(@"files:%@",files);

//5、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-----
//1、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];

//2、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"]; // 如果沒查找到，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，一旦被創建，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符串和時區。

以下是常用方法：

+(id)calendarDate; //創建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; //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

--------創建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，需要頻繁地將數據讀入一個臨時存儲區，它通常成爲緩衝區。

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緩存區最多可以存儲2GB的數據。

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）。

下面代碼展示瞭如何將文件的內容讀入內存緩衝區，然後再將緩衝區的內容寫入到另一個文件中。

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

http://liwpk.blog.163.com/blog/static/3632617020114794852539/

用法：NSNumber、NSString、NSDate、NSCalendarDate、NSData

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用法：NSNumber、NSString、NSDate、NSCalendarDate、NSData

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