Objective-C，从文本文件中获取字符串？

Question

I know there are a few different ways to find text in file, although I haven't found a way to return the text after the string I'm searching for. For example, if I was to search file.txt for the term foo and wanted to return bar , how would I do that without knowing it's bar or the length?

Here's the code I'm using:

if (!fileContentsString) {
    NSLog(@"Error reading file");
}

// Create the string to search for
NSString *search = @"foo";

// Search the file contents for the given string, put the results into an NSRange structure
NSRange result = [fileContentsString rangeOfString:search];

// -rangeOfString returns the location of the string NSRange.location or NSNotFound.
if (result.location == NSNotFound) {
    // foo not found. Bail.
    NSLog(@"foo not found in file");
    return;
}
// Continue processing
NSLog(@"foo found in file");    
}

Answer 1

You might want to use RegexKitLite and perform a regex look up:

NSArray * captures = [myFileString componentsMatchedByRegex:@"foo\\s+(\\w+)"];
NSString * wordAfterFoo = captures[1];

Not test though.

Answer 2

you could use [NSString substringFromIndex:]

if (result.location == NSNotFound) 
{
    // foo not found. Bail.
    NSLog(@"foo not found in file");
    return;
}    
else    
{
    int startingPosition = result.location + result.length;
    NSString* foo = [fileContentsString substringFromIndex:startingPosition]        
    NSLog(@"found foo = %@",foo);  
}