Objective-C学习笔记－NSString

来源：互联网发布：java 当前时间转整型编辑：程序博客网时间：2024/06/05 15:51

OC的不可变字符串

OC 字符串的创建方式

直接赋值

    NSString *str=@"hello world";//oc的字符串必须加上@符号

手动实例化

    NSString *str=[[NSString alloc] init];    str=@"hello ios";

字符串的常用操作

c字符串和oc字符串的互相转化

    char *cStr="I am c";//c语言字符串    NSString *nsStr=[NSString stringWithUTF8String:cStr]//转换成oc    NSString *str=@"I am oc";//oc字符串    char *c=[str UTF8String];//转换成c字符串

字符串的简单格式化输出

    NSString *name=@"kobe":    int age=38;    NSLog(@"hello I'am %@,I'am $d years old",name,age);hello I'an kobe,I'an 30 years old

字符串的拼接

    NSString *str1=@"hello":    NSString *str2=@"world";    NSString *Str3=[str1 stringByAppendingString:str2];

字符串的大小写转换

    NSString *str=@"hello";    NSString *str2=[str uppercaseString];    NSLog(@"after change=%@",str2);//HELLO    NSString *str3=[str2 lowercaseString];    NSLog(@"after change=%@",str3);//hello

是否包涵前缀

    NSString *str=@"kobe is a NBA player";    BOOL hasPrefix=[str hasPrefix:@"kobe"];    NSLog(@"result=%@",hasPrefix);    BOOL hasSuffix=[str hasSuffix:@"player"];    NSLog(@"result=%@",hasSuffix);

文件的读写

    NSString *fileUrl=@"your path":    NSString *fileStr=[NSString stringWithContentsOfFile:fileUrl encoding:NSUTF8StringEncoding error:nil];    NSLog(@"file Contents is:%@",fileStr);    NSString *needWriteString=@"hello android,I'am ios";    BOOL isSuccess=[needWriteString writeToFile:@"your path" atomically:YES encoding:NSUTF8StringEncoding error:nil];    if(isSuccess){        NSLog(@"write success");    }else{        NSLog(@"write failure");    }

未完待续

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