CODEWITHSUNDEEP
iphoneobjective-cregexios5nsstring
jer-k
jer-k

Reputation: 1423

Get the extension of a file contained in an NSString

I have an NSMutable dictionary that contains file IDs and their filename+extension in the simple form of fileone.doc or filetwo.pdf. I need to determine what type of file it is to correctly display a related icon in my UITableView. Here is what I have done so far.

NSString *docInfo = [NSString stringWithFormat:@"%d", indexPath.row]; //Determine what cell we are formatting
NSString *fileType = [contentFiles objectForKey:docInfo]; //Store the file name in a string

I wrote two regex to determine what type of file I'm looking at, but they never return a positive result. I haven't used regex in iOS programming before, so I'm not entirely sure if I'm doing it right, but I basically copied the code from the Class Description page. 

    NSError *error = NULL;
NSRegularExpression *regexPDF = [NSRegularExpression regularExpressionWithPattern:@"/^.*\\.pdf$/" options:NSRegularExpressionCaseInsensitive error:&error];
NSRegularExpression *regexDOC = [NSRegularExpression regularExpressionWithPattern:@"/^.*\\.(doc|docx)$/" options:NSRegularExpressionCaseInsensitive error:&error];
    NSUInteger numMatch = [regexPDF numberOfMatchesInString:fileType options:0 range:NSMakeRange(0, [fileType length])];
    NSLog(@"How many matches were found? %@", numMatch);

My questions would be, is there an easier way to do this? If not, are my regex incorrect? And finally if I have to use this, is it costly in run time? I don't know what the average amount of files a user will have will be.

Thank you.

Upvotes: 55

Views: 42083

Answers (6)

Ashu
Ashu

Reputation: 3523

Try this, it works for me.

NSString *fileName = @"yourFileName.pdf";
NSString *ext = [fileName pathExtension];

Documentation here for NSString pathExtension

Upvotes: 3

Domenico
Domenico

Reputation: 1491

In Swift 3 you could use an extension:

extension String {

public func getExtension() -> String? {

        let ext = (self as NSString).pathExtension

        if ext.isEmpty {
            return nil
        }

        return ext
    }
}

Upvotes: 0

Aatish Javiya
Aatish Javiya

Reputation: 71

Try this : 

NSString *fileName = @"resume.doc";  
NSString *ext = [fileName pathExtension];

Upvotes: 4

David Barry
David Barry

Reputation: 2638

You're looking for [fileType pathExtension]

NSString Documentation: pathExtension

Upvotes: 155

remy
remy

Reputation: 1501

//NSURL *url = [NSURL URLWithString: fileType];
NSLog(@"extension: %@", [fileType pathExtension]);

Edit you can use pathExtension on NSString

Thanks to David Barry

Upvotes: 7

Eric
Eric

Reputation: 2043

Try using [fileType pathExtension] to get the extension of the file.

Upvotes: 1

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