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

• 用法总结：NSNumber、NSString、NSDate、NSCalendarDate、NSData(待续)

  分类： ios2012-03-13 21:09 6267人阅读 评论(4) 收藏 举报
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  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 -> NSData：

  NSData *fileData2 = [strData dataUsingEncoding:NSUTF8StringEncoding];

  NSMutableData