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 }