【黑马程序员】————Foundation框架02常用类—字符类

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常用类

NSString

->NSMutableString

NSArray

->NSMutableArray

NSSet

->NSMutableSet

NSDictionary

->NSMutableDictionary

NSDate

NSObject

字符类-NSString/NSMutableString

NSString : 不可变字符串
 
 NSMutableString : 可变字符串

 1 void stringCreate()
 2 {
 3     /*
 4      1.字符串的创建
 5      */
 6     NSString *s1 = @"jack";
 7
 8     //NSString *s2 = [[NSString alloc] initWithString:@"jack"];
 9
10     NSString *s3 = [[NSString alloc] initWithFormat:@"age is %d", 10];
11
12     // C字符串 --> OC字符串
13     NSString *s4 = [[NSString alloc] initWithUTF8String:"jack"];
14     // OC字符串 --> C字符串
15     const char *cs = [s4 UTF8String];
16
17     // NSUTF8StringEncoding 用到中文就可以用这种编码
18     NSString *s5 = [[NSString alloc] initWithContentsOfFile:@"/Users/apple/Desktop/1.txt" encoding:NSUTF8StringEncoding error:nil];
19
20
21     // URL : 资源路径
22     // 协议头://路径
23     // file://
24     // ftp://
25     // http://weibo.com/a.png
26
27
28
29
30     // NSURL *url = [[NSURL alloc] initWithString:@"file:///Users/apple/Desktop/1.txt"];
31     NSURL *url = [NSURL fileURLWithPath:@"/Users/apple/Desktop/1.txt"];
32
33     NSString *s6 = [[NSString alloc] initWithContentsOfURL:url encoding:NSUTF8StringEncoding error:nil];
34     NSLog(@"s6=\n%@", s6);
35
36
37     /*
38      一般都会有一个类方法跟对象方法配对
39      [NSURL URLWithString:<#(NSString *)#>];
40      [NSString stringWithFormat:@""];
41      [NSString stringWithContentsOfFile:<#(NSString *)#> encoding:<#(NSStringEncoding)#> error:<#(NSError *__autoreleasing *)#>];
42
43      */
44
45 }

 1 void stringExport()
 2 {
 3     // 字符串的导出
 4     [@"Jack\nJack" writeToFile:@"/Users/apple/Desktop/my.txt" atomically:YES encoding:NSUTF8StringEncoding error:nil];
 5
 6
 7     NSString *str = @"4234234";
 8     NSURL *url = [NSURL fileURLWithPath:@"/Users/apple/Desktop/my2.txt"];
 9     [str writeToURL:url atomically:YES encoding:NSUTF8StringEncoding error:nil];
10 }

 1 void stringExport()
 2 {
 3        NSMutableString *s1 = [NSMutableString stringWithFormat:@"my age is 10"];
 4     // 拼接内容到s1的后面
 5     [s1 appendString:@" 11 12"];
 6
 7     // 获取is的范围
 8     NSRange range = [s1 rangeOfString:@"is"];
 9     // 删除
10     [s1 deleteCharactersInRange:range];
11
12
13     NSString *s2 = [NSString stringWithFormat:@"age is 10"];
14     //新创了一个字符串
15
16     NSString *s3 = [s2 stringByAppendingString:@" 11 12"];
17
18
19     NSLog(@"s1=%@, s2=%@", s1, s2);
20
21     return 0;
22 }