1.NSString与路径

• -(BOOL)isAbsolutePath;
  • 是否为绝对路径

     // 其实就是判断是否以/开头
//    NSString *str = @"/Users/WJim/Desktop/Objective-CJiChuXueXi/Day7/cwj.txt";
    NSString *str = @"Users/WJim/Desktop/Objective-CJiChuXueXi/Day7/cwj.txt";
    if ([str isAbsolutePath]) {
        NSLog(@"是绝对路径");
    }else
    {
        NSLog(@"不是绝对路径");
    }

• -(NSString *)lastPathComponent;
  • 获得最后一个目录

    // 截取最后一个/后面的内容
    NSString *str = @"/Users/WJim/Desktop/Objective-CJiChuXueXi/Day7/cwj.txt";
    NSString *component = [str lastPathComponent];
    NSLog(@"component = %@", component);

• -(NSString *)stringByDeletingLastPathComponent;
  • 删除最后一个目录

    // 其实就是上次最后一个/和之后的内容
    NSString *str = @"/Users/WJim/Desktop/Objective-CJiChuXueXi/Day7/cwj.txt";
    NSString *newStr = [str stringByDeletingLastPathComponent];
    NSLog(@"newStr = %@", newStr);

• -(NSString )stringByAppendingPathComponent:(NSString )str;
  • 在路径的后面拼接一个目录 (也可以使用stringByAppendingString:或者stringByAppendingFormat:拼接字符串内容)

// 其实就是在最后面加上/和要拼接得内容
    // 注意会判断后面有没有/有就不添加了, 没有就添加, 并且如果有多个会替换为1个
//    NSString *str = @"/Users/WJim/Desktop/Objective-CJiChuXueXi/Day7/cwj.txt";
    NSString *str = @"/Users/WJim/Desktop/Objective-CJiChuXueXi/Day7/cwj.txt/";
    NSString *newStr = [str stringByAppendingPathComponent:@"lnj"];
    NSLog(@"newStr = %@", newStr);

2.NSString与文件拓展名

• -(NSString *)pathExtension;
  • 获得拓展名

    // 其实就是从最后面开始截取.之后的内容
//    NSString *str = @"cwj.txt";
    NSString *str = @"abc.cwj.txt";
    NSString *extension = [str pathExtension];
    NSLog(@"extension = %@", extension);

• -(NSString *)stringByDeletingPathExtension;
  • 删除尾部的拓展名

    // 其实就是上次从最后面开始.之后的内容
//    NSString *str = @"cwj.txt";
    NSString *str = @"abc.cwj.txt";
    NSString *newStr = [str stringByDeletingPathExtension];
    NSLog(@"newStr = %@", newStr);

• -(NSString )stringByAppendingPathExtension:(NSString )str;
  • 在尾部添加一个拓展名

// 其实就是在最后面拼接上.和指定的内容
    NSString *str = @"cwj";
    NSString *newStr = [str stringByAppendingPathExtension:@"txt"];
    NSLog(@"newStr = %@", newStr);