前言

1.Foundation基础
2.framework框架

1.Foundation框架的结构关系：

image.png image.png

2.Foundation基础:

OC和C之间的转换：

 1 int main(int argc, const char * argv[]) {
 2     @autoreleasepool {
 3         //C语言字符串
 4         char *ch = "Hello objective-c";
 5         NSString *ns = @"Hello c";
 6         //OC、C语言之间的转换
 7         //C语言->OC语言
 8         NSString *oc = [NSString stringWithUTF8String:ch];
 9         NSLog(@"转为oc语言的字符串：%@",oc);
10         //OC语言->C语言
11         const char *c = [ns UTF8String];
12         NSLog(@"转为c语言的字符串：%s",c);
13     }
14     return 0;
15 }

NSString的操作：

 1  int main(int argc, const char * argv[]) {
 2     @autoreleasepool {
 3         //创建字符串
 4         NSString *str1 = @"Hello world1!";
 5         NSString *str2 = [[NSString alloc] init];
 6         str2 = @"Hello world2";
 7         //格式化字符串
 8         int a = 10;
 9         int b = 20;
10         NSLog(@"%@",[NSString stringWithFormat:@"a=%d, b=%d",a,b]);
11         //拼接字符串
12         NSString *str3 = [str1 stringByAppendingString:str2];
13         NSLog(@"%@",str3);
14         //大小写转换
15         NSString *str4 = @"ABCDEF";
16         NSString *str5 = [str4 lowercaseString];
17         NSLog(@"%@",str5);
18         NSString *str6 = [str5 uppercaseString];
19         NSLog(@"%@",str6);
20         //前缀后缀的判断
21         NSString *str7 = @"www.goodboy.heyang";
22         BOOL hasPreFix = [str7 hasPrefix:@"www"];
23         if (hasPreFix) {
24             NSLog(@"str7有 www 的前缀。");
25         }
26         BOOL hasSufFix = [str7 hasSuffix:@"heyang"];
27         if (hasSufFix) {
28             NSLog(@"str7有 heyang 后缀。");
29         }
30     }
31     return 0;
32 }

NSString比较字符串：

 1 int main(int argc, const char * argv[]) {
 2     @autoreleasepool {
 3         //判断两个字符串是否相同
 4         NSString *str1 = @"Hello";
 5         NSString *str2 = @"Hello";
 6         if ([str1 isEqualToString:str2]) {
 7             NSLog(@"两个字符是一致的。");
 8         }else{
 9             NSLog(@"不一致！");
10         }
11         
12         //比较字符串
13         //NSComparisonResult需要自己去查阅相关的资料
14         
15         //分割，按照指定字符分割字符串
16         NSString *str3 = @"a,b,c,d,e,f,g";
17         NSArray *strArray = [str3 componentsSeparatedByString:@","];
18         for(NSString *str in strArray){
19             NSLog(@"str = %@",str);
20         }
21         /*验证正则表达式失败
22         NSString *str4 = @"1+2-3/9";
23         NSArray *strArray2 = [str4 componentsSeparatedByString:@"[\+\-\*\/]"];
24         for(NSString *str in strArray2){
25             NSLog(@"str = %@",str);
26         }
27         */
28         //按照范围截取字符串,注意这里是结构体实例，所以不需要指针
29         NSRange range = NSMakeRange(1, 5);//前面是截取的起点，后面是长度，于是截取的是1～4
30         NSString *str5 = [str3 substringWithRange:range];
31         NSLog(@"str5 = %@",str5);
32         //从某一位开始截取后面的字符串
33         NSString *str6 = [str3 substringFromIndex:2];
34         NSLog(@"str6 = %@",str6);
35         //从开始截取到某一位
36         NSString *str7 = [str3 substringToIndex:2];
37         NSLog(@"str7 = %@",str7);
38         
39         //将字符串拆分为每一个字符
40         for (int i = 0; i<[str3 length]; i++) {
41             NSLog(@"%c ",[str3 characterAtIndex:i]);
42         }
43     }
44     return 0;
45 }