IOS NSString 截取，objectAtIndex，rangeOfString，stringWithContentsOfFile，NSEnumerator

小结：

1）componentsSeparatedByString:截取指定字符串；

2) pathForResource：获取程序运行时目录

3)  objectAtIndex:获取当前索引的字符串；

4)  rangeOfString:获取指定短字符串在长字符串中的开始，结尾索引值；

5) stringWithContentsOfFile：按行读取文件

6) componentsSeparatedByString:@"\n"];换行分割字符串；

7) NSEnumerator *nse = [lines objectEnumerator]; 将数组转换为NSEnumerator，可向前读取数据；

8)  nextObject：读取下一行数据；

void splitString(){

NSString *animals = @"dog#cat#pig";

//将#分隔的字符串转换成数组

NSArray *array = [animals componentsSeparatedByString:@"#"];

NSLog(@"animals:%@",array);

//获取程序运行时目录

NSString *escapedPath = [[NSBundle mainBundle] pathForResource:@"info" ofType:@"plist"];

NSArray *strings = [escapedPath componentsSeparatedByString: @"/"];

NSString *tmpFilename  = [strings objectAtIndex:[strings count]-1];

NSRange iStart = [escapedPath rangeOfString : tmpFilename];

NSString *runtimeDirectory = [escapedPath substringToIndex:iStart.location-1];

NSLog(@"runtimeDirectory:%@",runtimeDirectory);

//按行读取文件

NSString *tmp;

NSArray *lines = [[NSString stringWithContentsOfFile:@"test.txt" encoding:nil error:nil] 

  componentsSeparatedByString:@"\n"];

NSEnumerator *nse = [lines objectEnumerator];

while(tmp = [nse nextObject]) {

NSLog(@"tmp:%@", tmp);

}

}