Substring after substring in NSString

Question

I am new in objective and I'm facing my first problem, and I can not continue my first project.

it's quite simple, I have a NSString :

NSString *myString = @"<font face='Helvetica' size=25 color='#d79198'> Here is some text !</font>";

what I want to do is to get the value of the size "25" which is always 2 char long, so I can calculate my UILabel size.

i know how to detect if there is the substring I am looking for "size=" using :

if ([string rangeOfString:@"bla"].location == NSNotFound)

but I have not found or not understand how to extract the string @"size=XX" and then get the XX as a NSString from *myString

Thank for any help.

Just generally speaking, you could use a "regular expression", or you could use componentsSeparatedByString. With the latter you may need to examine each resulting "component" with hasPrefix to find the one that begins "size=". — Hot Licks, Apr 06 '13 at 12:20

score 2 · Answer 1 · answered Apr 06 '13 at 12:05

2

NSString *myString = @"<font face='Helvetica' size=25 color='#d79198'> Here is some text !</font>";
    if ([myString rangeOfString:@"size"].location != NSNotFound)
    {
        myString = [myString substringFromIndex:[myString rangeOfString:@"size"].location]; 
        myString = [myString substringToIndex:[myString rangeOfString:@" "].location]; // Now , myString ---> size=25 color='#d79198'> Here is some text !</font> 
        myString = [myString substringFromIndex:[myString length]-2];// Now, myString ---> size=25
        NSLog(@"myString -- %@",myString); // Now, myString ---> 25
    }

answered Apr 06 '13 at 12:05

Manu

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Just as if you were trying to [parse HTML using regular expressions](http://stackoverflow.com/questions/1732348/regex-match-open-tags-except-xhtml-self-contained-tags/1732454#1732454). You **shall not.** – Apr 06 '13 at 12:07
@H2CO3 hmm... regular expressions... * looking guilty * – David Rönnqvist Apr 06 '13 at 12:13

score 2 · Accepted Answer · edited Apr 06 '13 at 12:08

2

NSString *myString = @"<font face='Helvetica' size=25 color='#d79198'> Here is some text !</font>";
NSRange range = [myString rangeOfString:@"size="];
if (range.location != NSNotFound)
{
    NSLog(@"Found \"size=\" at %d", range.location);
    NSString *sizeString = [myString substringWithRange:NSMakeRange(range.location+5, 2)];
    NSLog(@"sizeString: %@", sizeString);
}

This should do the trick. You could also at the end do this: int sizeFont = [sizeString intValue];

edited Apr 06 '13 at 12:08

David Rönnqvist

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answered Apr 06 '13 at 12:07

Larme

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Note that rangeOfString returns length==0 if the target string is not found. So checking for length is better than location. If the receiver is nil, the length and location are both returned as 0, not NSNotFound. – Reefwing Dec 12 '17 at 06:35

score 1 · Answer 3 · answered Jul 10 '13 at 13:11

If you have string like stack:overflow then use it as follow :

 NSString *Base=@"stack:overflow"
 NSString *one  = [[Base componentsSeparatedByString:@":"] objectAtIndex:0];
 NSString *two  = [[Base componentsSeparatedByString:@":"] objectAtIndex:1];

In this case one = stack and two=overflow

score 0 · Answer 4 · answered Apr 06 '13 at 12:07

0

Part of an HTML page? Then use the tool that is designed for the task.

answered Apr 06 '13 at 12:07

3

What's wrong with this answer? This is the **only correct answer** so far. – Apr 06 '13 at 12:21
Non i use this because of colored UILabel – user2252092 Apr 06 '13 at 15:16

score 0 · Answer 5 · answered Apr 06 '13 at 12:07

You could calculate the range of the number yourself or use a very simple regular expression to get the substring, something like

(?<=size\=)\d*

This means that you are searching for digits (\d*) that is preceded by "size=" ((?<=size\=))

Which using NSRegularExpression would be

NSError *error = NULL;
NSRegularExpression *regex = 
  [NSRegularExpression regularExpressionWithPattern:@"(?<=size\\=)\\d*" 
                                            options:0 
                                              error:&error];
NSTextCheckingResult *match = 
  [regex firstMatchInString:myString 
                    options:0 
                      range:NSMakeRange(0, [myString length])];
NSString *sizeText = [myString substringWithRange:match.range];

Finally you should convert the text "25" into a number using

NSInteger size = [sizeText integerValue];

First time i use NSRegularExpression, thanks for the tip David. — user2252092, Apr 06 '13 at 15:17

score -1 · Answer 6 · answered Apr 06 '13 at 12:10

Use componentsSeparatedByString: method...

NSString *myString = @"<font face='Helvetica' size=25 color='#d79198'> Here is some text !</font>";
    NSString *theSizeString = [[[[myString componentsSeparatedByString:@" "] objectAtIndex:2] componentsSeparatedByString:@"="] objectAtIndex:1];
    NSLog(@"The sizestring:%@",theSizeString);

I think it will be helpful to you.

score -1 · Answer 7 · answered Apr 06 '13 at 12:12

You can get the range of the string @"size=". The range has location and length. So what you need next is to call on the myString the substringWithRange: method. The parameter would be an NSRage starting from the location+length of @"size=" and length of 2.

Substring after substring in NSString

7 Answers7