2.Foundation框架之NSString的使用

 1 #import <Foundation/Foundation.h> 2  3 /** 4  NSString:不可变字符串 5  NSMutableString:可变字符串 6  */ 7  8 int main(int argc, const char * argv[]) { 9     @autoreleasepool {10         /** 1.字符串的创建 */11         NSString *s1 = @"Chris Paul";12         NSString *s2 = [[NSString alloc] initWithFormat:@"Magic Johnson"];13         14         /** C字符串 --> OC字符串 */15         NSString *s3 = [[NSString alloc] initWithUTF8String:"Kobe Bryant"];16         17         /** OC字符串 --> C字符串 */18         const char * cs = [s3 UTF8String]; /** const常量 */19         20         /** NSUTF8StringEncoding 用到中文就可以用这种编码，记住即可 */21         NSString *s4 = [[NSString alloc] initWithContentsOfFile:@"/Users/tusdk/Desktop" encoding:NSUTF8StringEncoding error:nil];22         23         /** URL:资源路径24             协议头://路径25             file://     本地文件26             ftp://      服务器文件27          */28         NSURL *url = [[NSURL alloc] initWithString:@"http://www.wuhunews.cn"];29         NSString *s5 = [[NSString alloc] initWithContentsOfURL:url encoding:NSUTF8StringEncoding error:nil];30         NSLog(@"%@", s5);31         32         /**33          一般都有个类方法与对象方法配对34          [NSURL URLWithString:(NSString *)];35          [NSString stringWithFormat:(NSString *), ...];36          [NSString stringWithContentsOfFile:(NSString *) encoding:(NSStringEncoding) error:(NSError *__autoreleasing *)];37 38          [NSURL fileURLWithPath:(NSString *)]; // 有点特殊39         */40         41         42         /** 字符串写入文件 */43         [@"Michael Jordan" writeToFile:@"/Users/tusdk/Desktop/Michael Jordan.m" atomically:YES encoding:NSUTF8StringEncoding error:nil];44         /** atomically:YES 原子性:如果中途写入失败，test.docx不会被创建 */45         46         /** 可变字符串的创建与拼接 */47         NSMutableString *s6 = [NSMutableString stringWithFormat:@"Chris Paul"];48         [s6 appendFormat:@"Magic Johnson"]; /** 拼接内容到s6的后面 */49         50         /** 删除字符串方法1: */51         [s6 deleteCharactersInRange:NSMakeRange(4, 2)]; /** 4是起点,2是长度*/52         /** 删除字符串方法2: */53         NSRange range = [s6 rangeOfString:@"Paul"];54         [s6 deleteCharactersInRange:range];55         56         NSLog(@"%@", s6);57         58         NSString *s7 = [s6 stringByAppendingString:@"Michael Jordan, Kobe Bryant"];59     }60     return 0;61 }