(转载)iphone 用法总结：NSNumber、NSString、NSDate、NSCalendarDate、NSData

    

NSNumber

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

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

– (int)intValue;

– (double)doubleValue;

//NSNumber可以将基本数据类型包装起来，形成一个对象，这样就可以给其发送消息，装入NSArray中等等。

NSNumber * intNumber=[NSNumber numberWithInt：100]；

NSNumber *floatNumber=[NSNUmber numberWithFloat:100.00];

int i=[intNumber intValue]；

if([intNumber isEqualToNumber:floatNumber]) ….

//NSNumber继承NSObject ，可以使用比较 compare： isEqual等消息

NSString

//一个NSString对象可以存储一段Unicode字符。在cocoa中，所有和字符、字符串相关的处理都是使用NSString来完成。

NSObject -> NSString         // NSString继承自NSObject

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

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

+(id) stringWithString:nsstring;     //创建一个新的字符串，并将其设置为nsstring

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

-(id)initWithString:nsstring;         //将分配的字符串设置为nsstring

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

– (BOOL)hasPrefix:(NSString *)string;

– (int)intValue;

– (double)doubleValue;

– (NSString *)stringByAppendingString:(NSString *)string;    // 给一个字符串附加一个字符串string。

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

– (NSString *)stringByDeletingPathComponent;

    

//—–创建字符串的方法—–

//1、创建常量字符串

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

//2、先创建一个空的字符串，然后赋值；

//        alloc和init组合则适合在函数之间传递参数，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、创建临时字符串

        NSString *astring;

        astring = [NSString stringWithCString:”This is a temporary string”];

        NSLog(@”astring:%@”,astring);

// OR

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

//5、创建格式化字符串:占位符（由一个%加一个字符组成）

        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];

//—–从文件读取字符串—–

        NSString *path = @”astring.text”;

        NSString *astring = [[NSString alloc] initWithContentsOfFile:path];

        NSLog(@”astring:%@”,astring);

        [astring release];

//—–写字符串到文件—-        

        NSString *astring = [[NSString alloc] initWithString:@”This is a String!”];

        NSLog(@”astring:%@”,astring);

        NSString *path = @”astring.text”;        

        [astring writeToFile: path atomically: YES];

        [astring release];        

//—–比较两个字符串—–

//1、用C比较:strcmp函数

        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返回的三种值：NSOrderedSame，NSOrderedAscending，NSOrderedDescending)        

        NSString *astring01 = @”This is a String!”;

        NSString *astring02 = @”This is a String!”;        

        BOOL result = [astring01 compare:astring02] = = NSOrderedSame;     //NSOrderedSame// 判断两者内容是否相同

        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// 判断两对象值的大小(按字母顺序进行比较，astring02大于astring01为真)

        NSString *astring01 = @”this is a String!”;

        NSString *astring02 = @”This is a String!”;

        BOOL result = [astring01 compare:astring02] = = NSOrderedDescending;        

        NSLog(@”result:%d”,result);            

        //NSOrderedDescending 判断两对象值的大小(按字母顺序进行比较，astring02小于astring01为真)

//4、不考虑大小写比较字符串1

        NSString *astring01 = @”this is a String!”;

        NSString *astring02 = @”This is a String!”;

        BOOL result = [astring01 caseInsensitiveCompare:astring02] = = NSOrderedSame;        

        NSLog(@”result:%d”,result);            

        //NSOrderedDescending判断两对象值的大小(按字母顺序进行比较，astring02小于astring01为真)

//5、不考虑大小写比较字符串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:不区分大小写比较 NSLiteralSearch:进行完全比较，区分大小写 NSNumericSearch:比较字符串的字符个数，而不是字符值。

//—–改变字符串的大小写—–

        NSString *string1 = @”A String”;

        NSString *string2 = @”String”;

        NSLog(@”string1:%@”,[string1 uppercaseString]);//uppercaseString返回转换为大写的字符串

        NSLog(@”string2:%@”,[string2 lowercaseString]);//lowercaseString返回转换为小写的字符串

        NSLog(@”string2:%@”,[string2 capitalizedString]);//capitalizedString返回每个单词首字母大写的字符串

//—–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: 从字符串的开头一直截取到指定的位置，但不包括该位置的字符

        NSString *string1 = @”This is a string”;

        NSString *string2 = [string1 substringToIndex:3];    

        NSLog(@”string2:%@”,string2);

//2、-substringFromIndex: 以指定位置开始（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: //按照所给出的位置，长度，任意地从字符串中截取子串

        NSString *string1 = @”This is a string”;

        NSString *string2 = [string1 substringWithRange:NSMakeRange(0, 4)];

        NSLog(@”string2:%@”,string2);

//4、快速枚举

        for(NSString *filename in direnum)        {

                if([[filename pathExtension] isEqualToString:@”jpg”]){

                        [files addObject:filename];

                }

        }

        NSLog(@”files:%@”,files);    

//5、枚举

        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];    

//—–切分数组—–

//1、从字符串分割到数组－ componentsSeparatedByString:

        NSString *string = [[NSString alloc] initWithString:@”One,Two,Three,Four”];

        NSLog(@”string:%@”,string);        

        NSArray *array = [string componentsSeparatedByString:@”,”];

        NSLog(@”array:%@”,array);

        [string release];

//2、从数组合并元素到字符串- componentsJoinedByString:

        NSArray *array = [[NSArray alloc] initWithObjects:@”One”,@”Two”,@”Three”,@”Four”,nil];

        NSString *string = [array componentsJoinedByString:@”,”];

        NSLog(@”string:%@”,string);

//—–从目录搜索扩展名为jpg的文件—–

//NSFileManager *fileManager = [NSFileManager defaultManager];

        NSString *home;

        home = @”../Users/”;

        NSDirectoryEnumerator *direnum;

        direnum = [fileManager enumeratorAtPath: home];

        NSMutableArray *files = [[NSMutableArray alloc] init];

//枚举

        NSString *filename;

        while (filename = [direnum nextObject]) {

                if([[filename pathExtension] hasSuffix:@”jpg”]){

                        [files addObject:filename];

                }

        }

//扩展路径    

        NSString *Path = @”~/NSData.txt”;

        NSString *absolutePath = [Path stringByExpandingTildeInPath];

        NSLog(@”absolutePath:%@”,absolutePath);

        NSLog(@”Path:%@”,[absolutePath stringByAbbreviatingWithTildeInPath]);

//文件扩展名

        NSString *Path = @”~/NSData.txt”;

        NSLog(@”Extension:%@”,[Path pathExtension]);

//—–查找与替换—–

– (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, …;

//—–给字符串分配容量—–

        //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给出范围删除字符—-        

         //deleteCharactersInRange:

         NSMutableString *String1 = [[NSMutableString alloc] initWithString:@”This is a NSMutableString”];

         [String1 deleteCharactersInRange:NSMakeRange(0, 5)];        // 删除指定范围（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给出的字符串—–

        //-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]];    //    在可变字符串的最后插入

//—-将已有的空符串换成其它的字符串—–

        //-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”];     // 如果没查找到，则 （subRange.location == NSNotFound）为真。

//—-按照所给出的范围替换的原有的字符—–

        //-setString:

        NSMutableString *String1 = [[NSMutableString alloc] initWithString:@”This is a NSMutableString”];

        [String1 replaceCharactersInRange:NSMakeRange(0, 4) withString:@”That”];         // 用于NSMutableString

        NSLog(@”String1:%@”,String1);

//—-在给定的范围内查找并替换—–

– (NSUInteger)replaceOccurrencesOfString:(NSString *)target withString:(NSString *)replacement options:(NSStringCompareOptions)opts range:(NSRange)searchRange

//—-判断字符串内是否还包含别的字符串(前缀，后缀)—–

//01： 检查字符串是否以另一个字符串开头- (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： 查找字符串某处是否包含给定的字符串 – (NSRange) rangeOfString: (NSString *) aString，这一点前面在串中搜索子串用到过

NSRange subRange;

subRange = [string1 rangeOfString:@”string A”];    //查找字符串string1中是否包含“string A”。返回NSRange类型。

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对象包含了日期和时间、时区以及一个带有格式的字符串，它从NSDate继承而来。

//NSCalendarDate对象是immutable的，一旦被创建，无法修改其中的时间和日期，当然可以修改那个带格式的字符串和时区。

//以下是常用方法：

+(id)calendarDate;    //创建当前日期和时间以及默认格式的NSCalendarDate对象，时区为机器设置好的时区。

+(id)dateWithYear:(int)year

        month:(unsigned)month

            day:(unsigned)day    

         hour:(unsigned)hour

     minute:(unsigned)minute

     second:(unsigned)second    

timeZone:(NSTimeZone    *)aTimeZone    

-(int)dayOfCommonEra;    //得到从公元1年算起，有多少天

-(int)dayOfMonth;                    //返回是月的第几天（1-31）

-(int)dayOfWeek;                    //返回是周的第几天 （0-6）

-(int)dayOfYear;                    //返回是年的第几天（1-366）

-(int)hourOfDay;                    // 返回是日的第几个小时（0-23）

-(void)setCalendarFormate:(NSString *)format    

//——–创建NSCalendarDate对象——–

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

//使用文件时，需要频繁地将数据读入一个临时存储区，它通常成为缓冲区。

//NSData类提供了一种简单的方式，它用来设置缓冲区、将文件的内容读入缓冲区，或将缓冲区的内容写到一个文件。

//对于32位应用程序，NSDATA缓存区最多可以存储2GB的数据。

//我们既可定义不变缓冲区（NSData类），也可定义可变的缓冲区（NSMutableData类）。

//下面代码展示了如何将文件的内容读入内存缓冲区，然后再将缓冲区的内容写入到另一个文件中。

NSData *fileData;NSFileManager *fileManager = [[NSFileManager alloc]init];fileData = [fileManager contentsAtPath:path];    [fileManager createFileAtPath:path2 contents:fileData attributes:nil];     //采用默认的属性值

//类型转换 NSData -> NSString：

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

//类型转换 NSString -> NSDat