NSValue/NSNumber

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Foundation框架下的基本类

NSValue/NSNumber

功能

将OC和C语言当中的基本数据类型转换成实例对象，即将值类型转换成引用类型

OC和C中的基本数据类型        int a = 5;        float b = 4.5;        double c = 34.5545;        char d = 'c';//        CGPoint point = {3,5};//        CGSize size = {30,47};//        CGRect rect = {point,size};        CGPoint point = CGPointMake(3, 5);        CGSize size = CGSizeMake(40, 60);        CGRect rect = CGRectMake(3, 5, 40, 60);        NSRange range = NSMakeRange(3, 7);        NSEdgeInsets edgeInsets = NSEdgeInsetsMake(10, 10, 10, 10);

NSValue 为 NSNumber 的父类.
其中NSValue类可以将CGPoint、CGSize、CGRect、NSRange、NSEdgeInsets转换成对象

 NSValue *pointValue = [NSValue valueWithPoint:point];        NSValue *sizeValue = [NSValue valueWithSize:size];        NSValue *rectValue = [NSValue valueWithRect:rect];        NSValue *rangeValue = [NSValue valueWithRange:range];        NSValue *edgeInsetsValue = [NSValue valueWithEdgeInsets:edgeInsets];

其中NSNumber类可以将int 、float、 double、 char、BOOL等C中基本数据类型转换成对象

NSNumber *intNumber = [NSNumber numberWithInt:1];        NSNumber *integerNumber = [NSNumber numberWithInteger:12];        NSNumber *floatNumber = [NSNumber numberWithFloat:12.3];        NSNumber *doubleNumber = [NSNumber numberWithDouble:12.455];        NSNumber *charNumber = [NSNumber numberWithChar:'a'];        NSNumber *boolNumber = [NSNumber numberWithBool:YES];

我们将C和OC中的基本数据类型（值类型）转换成对象（引用类型）的过程，叫做封装。相对应的，也有一个将对象转变成基本数据类型，此过程叫做拆包。

//拆包CGPoint point1 = [pointValue pointValue];        CGSize size1 = [sizeValue sizeValue];        CGRect rect1 = [rectValue rectValue];        NSRange range1 = [rangeValue rangeValue];        NSEdgeInsets edgeInsets1 = [edgeInsetsValue edgeInsetsValue];        int a1 = [intNumber intValue];        NSInteger a2 = [integerNumber integerValue];        float a3 = [floatNumber floatValue];        double a4 = [doubleNumber doubleValue];        char a5 = [charNumber charValue];        BOOL a6 = [boolNumber boolValue]

NSString / NSMutableString

OC中的字符串具有强大的功能，即封装性极强，我们只需要找到对应API，就可以对字符串做相应操作。OC中字符串分为 `不可变字符串` 和 `可变字符串`，其中`可变字符串`是`不可变字符串`的子类.在iOS开发中，字符串通常用作显示文本，即作为`UILabel`、`UITextFeild`等一些`UIKit`框架下控件的显示文本

NSString 不可变字符串

初始化字符串

1.快速初始化

NSString *string1 = @"bokanwisdom";

2.格式化的方式初始化字符串

NSString *string4 = [NSString stringWithFormat:@"%d%f%@",3,3.14,@"dajiahao"];

note:对于用格式化方式来构造字符串实例来讲，其作用并不是仅仅来构造一个字符串对象，它还可以用来做字符串拼接

3.从本地文件中读取字符串

NSString *string7 = [NSString stringWithContentsOfFile:path encoding:NSUTF8StringEncoding error:&error];

NSString *string8 = [NSString stringWithContentsOfFile:path usedEncoding:&encoding error:&error];

4.从网络中读取一个字符串

NSURL *url = [NSURL URLWithString:@"http://www.baidu.com"];NSString *string9 = [NSString stringWithContentsOfURL:url encoding:4 error:&error];

字符串的操作

1.字符串长度

NSUInteger length = string10.length;

2.字符串的截取

       NSString *subStr1 = [string10 substringToIndex:8];       NSString *subStr2 = [string10 substringFromIndex:8];        NSString *subStr3 = [string10 substringWithRange:NSMakeRange(8, length-8)];

3.字符串比较

==:表示两个字符串内容和指针都相同

 if (subStr2 == subStr3) {            //内容和指针都相等时，才成立            NSLog(@"subStr2和subStr3相等");        }else{            NSLog(@"subStr2和subStr3不相等");        }

[subStr2 isEqualToString:subStr3]:表示两个字符串内容是否相同

  if ([subStr2 isEqualToString:subStr3]) {            NSLog(@"subStr2和subStr3内容相同");        }else{            NSLog(@"subStr2和subStr3内容不相同");        }

根据字符串拿到对应的range

NSRange range = [string10 rangeOfString:@"人家"];

5.判断字符串中是否有xx前缀或xx后缀

        NSString *string11 = @"www.baidu.com";        if ([string11 hasPrefix:@"http://"]) {            NSLog(@"含有此前缀");        }else{            NSLog(@"不含有此前缀");        }        NSString *string12 = @"sdfdf.jpg";        if([string12 hasSuffix:@".jpg"]||[string12 hasSuffix:@".png"]){            NSLog(@"含有此后缀");        }

6.字符串拼接

 NSString *string13 = [@"http://" stringByAppendingString:string11];        NSLog(@"string13 = %@",string13);        NSString *domainStr = @"http://baidu.com";        NSString *xxx = @"login";        //http://baidu.com/login       NSString *string14 = [NSString stringWithFormat:@"%@/%@",domainStr,xxx];        NSLog(@"string14 = %@",string14);        NSString *string15 = [domainStr stringByAppendingPathComponent:xxx];        NSLog(@"string15 = %@",string15);        //http://b.hiphotos.baidu.com/image/pic/item/e4dde71190ef76c666af095f9e16fdfaaf516741.jpg        NSString *imgPath = @"http://b.hiphotos.baidu.com/image/pic/item/e4dde71190ef76c666af095f9e16fdfaaf516741.jpg";        imgPath = [imgPath lastPathComponent];        NSLog(@"imgPath = %@",imgPath);        path = [path lastPathComponent];        NSLog(@"path = %@",path);        NSString *theImageName = @"lishucheng";       theImageName = [theImageName stringByAppendingPathExtension:@"png"];        NSLog(@"theImageName = %@",theImageName);

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