[轉(zhuǎn)] 用法總結(jié)：NSNumber、NSString、NSDate、NSCalendarDate、NSData

在網(wǎng)上看到的，感覺(jué)可以，轉(zhuǎn)過(guò)來(lái)整理了一下。

NSNumber

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

NSNumber可以將基本數(shù)據(jù)類型包裝起來(lái)，形成一個(gè)對(duì)象，這樣就可以給其發(fā)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(gè)NSString對(duì)象可以存儲(chǔ)一段Unicode字符。在cocoa中，所有和字符、字符串相關(guān)的處理都是使用NSString來(lái)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(chuàng)建一個(gè)新的字符串，并將其設(shè)置為nsstring

    -(id)initWithFormat:(NSString *)format, ...  ;
    -(id)initWithString:nsstring;     //將分配的字符串設(shè)置為nsstring
    -(BOOL)isEqualToString:(NSString *)string;
    -(BOOL)hasPrefix:(NSString *)string;
    -(int)intValue;
    -(double)doubleValue;

    -(NSString *)stringByAppendingString:(NSString *)string;  // 給一個(gè)字符串附加一個(gè)字符串string。
    -(NSString *)stringByAppendingFormat:(NSString *)string;
    -(NSString *)stringByDeletingPathComponent;
創(chuàng)建字符串的方法

1、創(chuàng)建常量字符串

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

2、先創(chuàng)建一個(gè)空的字符串，然后賦值；
alloc和init組合則適合在函數(shù)之間傳遞參數(shù)，用完之后需要手工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(chuàng)建臨時(shí)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(chuàng)建格式化字符串:占位符（由一個(gè)%加一個(gè)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(gè)字符串

1、用C比較:strcmp函數(shù)

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 判斷兩者內(nèi)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(duì)象值的大小(按字母順序進(jìn)行比較，astring02大于astring01為真)

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(duì)象值的大小(按字母順序進(jìn)行比較，astring02小于astring01為真)

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(duì)象值的大小(按字母順序進(jìn)行比較，astring02小于astring01為真)

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(qū)分大小寫比較 NSLiteralSearch:進(jìn)行完全比較，區(qū)分大小寫 NSNumericSearch:比較字符串的字符個(gè)數(shù)，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(zhuǎn)換為大寫的字符串
NSLog(@"string2:%@",[string2 lowercaseString]);//lowercaseString返回轉(zhuǎn)換為小寫的字符串
NSLog(@"string2:%@",[string2 capitalizedString]);//capitalizedString返回每個(gè)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），并包括之后的全部字符

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(zhǎng)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?jǐn)?shù)組

1、從字符串分割到數(shù)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(shù)組合并元素到字符串- componentsJoinedByString:

NSArray *array = [[NSArray alloc] initWithObjects:@"One",@"Two",@"Three",@"Four",nil];
NSString *string = [array componentsJoinedByString:@","];
NSLog(@"string:%@",string);
從目錄搜索擴(kuò)展名為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(kuò)展路徑
NSString *Path = @"~/NSData.txt";
NSString *absolutePath = [Path stringByExpandingTildeInPath];
NSLog(@"absolutePath:%@",absolutePath);
NSLog(@"Path:%@",[absolutePath stringByAbbreviatingWithTildeInPath]);
文件擴(kuò)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刪除字符
 //deleteCharactersInRange:
 NSMutableString *String1 = [[NSMutableString alloc] initWithString:@"This is a NSMutableString"];
 [String1 deleteCharactersInRange:NSMakeRange(0, 5)]; //刪除指定范圍（location=0，length=5）的字符串
 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);
[String1 insertString:@"and StringEnd", atIndex:[String1 length]];//在可變字符串的最后插入
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(méi)查找到，則 （subRange.location == NSNotFound）為真。

按照所給出的范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"];     // 用于NSMutableString
NSLog(@"String1:%@",String1);
在給定的范圍內(nèi)查找并替換
-(NSUInteger)replaceOccurrencesOfString:(NSString *)target withString:(NSString *)replacement options:(NSStringCompareOptions)opts range:(NSRange)searchRange
判斷字符串內(nèi)是否還包含別的字符串(前綴，后綴)

1、檢查字符串是否以另一個(gè)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");

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

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(duì)象包含了日期和時(shí)間、時(shí)區(qū)以及一個(gè)帶有格式的字符串，它從NSDate繼承而來(lái)。
  • NSCalendarDate對(duì)象是immutable的，一旦被創(chuàng)建，無(wú)法修改其中的時(shí)間和日期，當(dāng)然可以修改那個(gè)帶格式的字符串和時(shí)區(qū)。

以下是常用方法：

+(id)calendarDate; //創(chuàng)建當(dāng)前日期和時(shí)間以及默認(rèn)格式的NSCalendarDate對(duì)象，時(shí)區(qū)為機(jī)器設(shè)置好的時(shí)區(qū)。

 +(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(gè)小時(shí)（0-23）
-(void)setCalendarFormate:(NSString *)format
創(chuàng)建NSCalendarDate對(duì)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(shí)，需要頻繁地將數(shù)據(jù)讀入一個(gè)臨時(shí)存儲(chǔ)區(qū)，它通常成為緩沖區(qū)。

  • NSData類提供了一種簡(jiǎn)單的方式，它用來(lái)設(shè)置緩沖區(qū)、將文件的內(nèi)容讀入緩沖區(qū)，或?qū)⒕彌_區(qū)的內(nèi)容寫到一個(gè)文件。
  • 對(duì)于32位應(yīng)用程序，NSDATA緩存區(qū)最多可以存儲(chǔ)2GB的數(shù)據(jù)。
    我們既可定義不變緩沖區(qū)（NSData類），也可定義可變的緩沖區(qū)（NSMutableData類）。

下面代碼展示了如何將文件的內(nèi)容讀入內(nèi)存緩沖區(qū)，然后再將緩沖區(qū)的內(nèi)容寫入到另一個(gè)文件中。

NSData *fileData;
NSFileManager *fileManager = [[NSFileManager alloc]init];
fileData = [fileManager contentsAtPath:path];  
[fileManager createFileAtPath:path2 contents:fileData attributes:nil];   //采用默認(rèn)的屬性值
類型轉(zhuǎn)換 NSData -> NSString：
NSString *strData = [[NSString alloc]initWithData:fileData encoding:NSASCIIStringEncoding];
類型轉(zhuǎn)換 NSString -> NSData：
NSData *fileData2 = [strData dataUsingEncoding:NSUTF8StringEncoding];

NSMutableData...（待續(xù)。。。）

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