1 NSString* str = [NSString stringWithFormat:@"曾经我打听过，你最近的生活 %@", @"love you"];2  NSLog(@"%@", str);

 1 　　　　 // 把C字符串转成OC的字符串对象 2         char* p = "I love beijing"; 3         NSString* testStr = [[NSString alloc] initWithFormat:@"%s",p ]; 4         NSLog(@"testString = %@",testStr); 5          6         // 把OC字符串对象转成C字符串 7         const char* newP = [testStr UTF8String]; 8         NSLog(@"newp = %s",newP); 9         10         // 与格式控制字符串构建对象的实例方法对应的类方法11         // 使用（Foundation框架里的）类方法创建的对象，由自动释放池管理内存12         NSString* str2 = [NSString stringWithFormat:@"This is a OC sting %d",109];13         NSLog(@"str2 = %@",str2);14         //=============================================15         // 使用一个现有的字符串对象构建一个新的字符串对象16         NSString* str = @"I‘m a oc string";17         NSString* str3 = [[NSString alloc] initWithString:str];18         NSLog(@"str3 = %@",str3);19         // 与之对应的类方法20         NSString* str4 = [NSString stringWithString:str];21         NSLog(@"str4 = %@",str4);22         23         //==============================================24         // 使用一个C字符串构建一个OC的字符串对象25         NSString* str5 = [[NSString alloc] initWithUTF8String:"This is a c String"];26         NSLog(@"str5 = %@",str5);27         // 与之对应的类方法28         NSString* str6 = [NSString stringWithUTF8String:"This is a c String"];29         NSLog(@"str6 = %@",str6);30         31         //==============================================32         // 使用文件内容构建一个字符串对象33         34         NSString* filePath = @"/Users/qianfeng/Desktop/test.txt";35         /* 36          第一个参数：读取的文件的路径37          第二个参数：指定编码集为NSUTF8String38          第三个参数：用于存放读取文件过程中的错误信息39          */40         NSError* error = nil;41         NSString* str7 = [NSString stringWithContentsOfFile:filePath encoding:NSUTF8StringEncoding error:nil];42         NSLog(@"str7 = %@",str7);

 1  //获取字符串长度（length） 2         NSString* str = [NSString stringWithFormat:@"曾经我打听过，你最近的生活 %@", @"love you"]; 3         NSUInteger lenth = [str length]; 4         NSLog(@"%ld", lenth); 5         NSLog(@"%@", str); 6         //NSRange 7         /* 8          NSRange在Foundation框架中定义如下 9          typedef struct _NSRange {10          NSUInteger location; //表示位置11          NSUInteger length; //长度12          } NSRange;13          */14         NSString* str2 = @"忙碌工作之余是否有运动?";15         NSString* subString = @"忙碌";16         //查找子串（从0开始）17         NSRange range = [str2 rangeOfString: subString];18         //打印框架内结构体的方法19         NSLog(@"%@", NSStringFromRange(range));20         //使用框架创建range21         NSRange newRange = NSMakeRange(5, 3);22         NSString* newTemp = [str2 substringWithRange: newRange];23         NSLog(@"%@", newTemp);24         //判断是否在父串中找到子串25         if (range.location == NSNotFound) {26             NSLog(@"Can‘t fount");27         }else{28             NSLog(@"Got it!");29         }30         //字符串比较（大小）31         NSString* strA = @"chengDu";32         NSString* strB = @"chongQing";33         //compare:方法的返回值类型为NSComparisonResult(枚举值)，其中34         //NSOrderedSame表示相等 NSOrderedAscending表示升序（小于）35         //NSOrderedDescending 表示降序(大于)36         if ([strA compare: strB] == NSOrderedSame) {37             NSLog(@"相等");38         }else if([strA compare: strB] == NSOrderedAscending){39             NSLog(@"小于");40         }else{41             NSLog(@"大于");42         }43         //字符串比较（是否相等）44         BOOL isEqule = [strA isEqualToString: strB];45         NSLog(@"The result is : %d", isEqule);46         47         //判断字符串前后缀48         NSString *fileString = @"/Users/student/DeskTop/file.txt";49         //判断前缀（hasPrefix:)方法50         BOOL isPrefix = [fileString hasPrefix:@"/Users"];51         //判断后缀 （hasSuffix:）方法52         BOOL isSuffix = [fileString hasSuffix: @".txt"];53         NSLog(@"isPrefix = %d, isSuffix = %d", isPrefix, isSuffix);54         //字符串转换为数字55         /*56          框架提供的字符串转换的方法如下：57          - (double)doubleValue;58          - (float)floatValue;59          - (int)intValue;60          - (NSInteger)integerValue NS_AVAILABLE(10_5, 2_0);61          - (long long)longLongValue NS_AVAILABLE(10_5, 2_0);62          - (BOOL)boolValue NS_AVAILABLE(10_5, 2_0);63          */64         NSString* strToNum = @"12345.234";65         int result = [strToNum intValue];66         NSLog(@"result = %d", result);