html src regexp iOS

Question

Need some hints on this simple regexp.

Regexp and target string code for extracting src from < img src="..." />

NSString *imgTag = @"<img alt=\"\" src=\"/sites/default/files/mypic.gif\" style=\"width: 300px; height: 195px;\" />";

NSRegularExpression *a = [NSRegularExpression regularExpressionWithPattern:@"src=\"(.*)\"" options:NSRegularExpressionCaseInsensitive error:nil];

Not sure if it has something to do with the options

NSTextCheckingResult *matches = [a firstMatchInString:imgTag options:NSMatchingReportProgress range:NSMakeRange(0, [imgTag length])];

NSRange matchRange = [matches range];
NSString *src = [imgTag substringWithRange:matchRange];
NSLog(@"%s, %@", __PRETTY_FUNCTION__, src);

Now the output is unexpected since it returns not only the group, but also everything after it up to the end tag.

Output

/sites/default/files/mypic.gif" style="width: 300px; height: 195px;

johankj · Accepted Answer · 2013-03-09 17:02:35Z

2

It is basically matching everything from the first " to the last ".

You should probably use the non-greedy operator ?, which "Matches 0 or more times. Matches as few times as possible.".
E.g.:

NSRegularExpression *a = [NSRegularExpression regularExpressionWithPattern:@"src=\"(.*?)\"" options:NSRegularExpressionCaseInsensitive error:nil];

answered Mar 9, 2013 at 17:02

johankj

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Comments

Richard Brown · Accepted Answer · 2013-03-09 17:00:54Z

1

Your regex is being greedy.

Try:

@"src=\"(.*?)\""

for your expression.

answered Mar 9, 2013 at 17:00

Richard Brown

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html src regexp iOS

Regexp and target string code for extracting src from < img src="..." />

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Regexp and target string code for extracting src from < img src="..." />

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