I'm trying to parse a 7-digit number from a page's source code and the pattern that I look for is
/nnnnnnn"
where "n" is a digit. I'm trying with the following regex and in a regex test site it works, but not in obj-c. Is it possible that I'm passing the wrong option or something?
NSRegularExpression *regex = [NSRegularExpression regularExpressionWithPattern:#"/\d\d\d\d\d\d\d\">" options:NSRegularExpressionSearch error:nil];
NSUInteger numberOfMatches = [regex numberOfMatchesInString:contents
options:0
range:NSMakeRange(0, [contents length])];
You should double the backslashes in front of your ds, like this:
#"/\\d\\d\\d\\d\\d\\d\\d\">"
Backslash is a special character inside a string literal: the character after it is interpreted differently. In order for the regex engine to see a backslash, you need two slashes in the literal.
Related
I want a regular expression for first name that can contain
1)Alphabets
2)Spaces
3)Apostrophes
Exp: Raja, Raja reddy, Raja's,
I used this ^([a-z]+[,.]?[ ]?|[a-z]+[']?)+$ but it is failing to recognise Apostrophes (').
- (BOOL)validateFirstNameOrLastNameOrCity:(NSString *) inputCanditate {
NSString *firstNameRegex = #"^([a-z]+[,.]?[ ]?|[a-z]+[']?)+$";
NSPredicate *firstNamePredicate = [NSPredicate predicateWithFormat:#"SELF MATCHES[c] %#",firstNameRegex];
return [firstNamePredicate evaluateWithObject:inputCanditate];
}
May I recommand ^[A-Z][a-zA-Z ']* ?
// The NSRegularExpression class is currently only available in the Foundation framework of iOS 4
NSError *error = NULL;
NSRegularExpression *regex = [NSRegularExpression regularExpressionWithPattern:#"^[A-Z][a-zA-Z ']*" options:NSRegularExpressionAnchorsMatchLines error:&error];
NSUInteger numberOfMatches = [regex numberOfMatchesInString:searchText options:0 range:NSMakeRange(0, [string length])];
return numberOfMatches > 1;
^[A-Z] : Force start with a capital letter from A to Z
[a-zA-Z ']* : followed by any number of charactere that an be 'a' to 'z', 'A' to 'Z', space or simple quote
I think you are looking for a pattern like this: ^[a-zA-Z ']+$
However, this is pretty bad. What about umlauts, accents, and a whole lot other letters that are not part of the ASCII alphabet?
A better solution would be to allow any kind of letter from any language.
To do so you can use the Unicode "letter" category \p{L}, e.g. ^[\p{L}]+$.
.. or you could just drop that rule all together - as reasonably suggested.
Say I have a string that looks like this:
iword/i
Here the tag is i. This is similar to an HTML tag except without the <> angle brackets.
Or say I have
emword/em
Here the tag is em.
What I want is a pattern that removes these tags.
I'm testing this pattern:
<([A-Z][A-Z0-9]*)\b[^>]*>(.*?)</\1> on http://rubular.com/, but it is not working properly.
Specifically, what I want to do is with Objective-C:
NSString *string = #"iword/i";
NSRegularExpression *regex = [NSRegularExpression regularExpressionWithPattern:pattern options:NSRegularExpressionCaseInsensitive error:&error];
return [regex stringByReplacingMatchesInString:string options:0 range:NSMakeRange(0, string.length) withTemplate:#""];
which will just remove all but word.
You're going to need a complete list of html tags you want to remove then (i, em, b, what else?) since you're going to have to search specifically for the tags to remove.
One way of doing this is: \b(i|em|b)(\w*)\/(i|em|b)\b (and as you've seen before with Obj-c, likely some double \ escaping)
In action: http://regex101.com/r/qL3cU9
Input:
iword/i
emword/em
bword/b
ibword/ib
notgoing/tomatch this
Substitution result:
word
word
word
ibword/ib
notgoing/tomatch this
I have a string:
[{"id":1,"gameName":"arizona","cost":"0.5E1","email":"hi#gmail.com","requests":0},{"id":2,"gameName":"arizona","cost":"0.5E1","email":"hi#gmail.com","requests":0},{"id":3,"gameName":"arizona","cost":"0.5E1","email":"hi#gmail.com","requests":0}]
However, I would like to parse this string into an array such as:
[{"id":1,"gameName":"arizona","cost":"0.5E1","email":"hi#gmail.com","requests":0},
{"id":2,"gameName":"arizona","cost":"0.5E1","email":"hi#gmail.com","requests":0},
{"id":3,"gameName":"arizona","cost":"0.5E1","email":"hi#gmail.com","requests":0}]
This array is delimited by the comma in between the curly braces: },{
I tride usign the command
NSArray *responseArray = [response componentsSeparatedByString:#","];
but this separates the string into values at EVERY comma, which is not desirable.
Then I tried using regex:
NSRegularExpression *regex = [NSRegularExpression regularExpressionWithPattern:#"\\{.*\\}" options:NSRegularExpressionCaseInsensitive error:&error];
NSArray *matches = [regex matchesInString:response options:0 range:NSMakeRange(0, [response length])];
which found one match: starting at the first curly brace to the last curly brace.
I was wondering if anyone new how to solve this problem efficiently?
This string seems to be valid JSON. Try a JSON parser: NSJSONSerialization
I agree with H2CO3's suggestion to use a parser where possible.
But looking at your attempted regex, it looks like you just need to make it non-greedy, i.e.
#"\\{.*?\\}"
^
|
Add this question mark for non-greedy matching.
Of course, this will fail if you have deeper levels of (what I assume to be) nested arrays. Go with the JSON parser!
I wrote the following code to eliminate anything after 3 dots
currentItem.summary = #"I am just testing. I am ... the second part should be eliminated";
NSError * error = NULL;
NSRegularExpression *regex = [NSRegularExpression regularExpressionWithPattern:#"(.)*(/././.)(.)*" options:0 error:&error];
if(nil != regex){
currentItem.summary = [regex stringByReplacingMatchesInString:currentItem.summary
options:0 range:NSMakeRange(0, [currentItem.summary length])
withTemplate:#"$1"];
}
However, my input and output are the same. The correct output should be "I am just testing. I am".
I was trying to do this using regular expression because I have a database of other regular expressions that I run on the string. I know the performance might not be as good as a plain text find or replace but the strings involved are short. I also tried using "\" to escape the dots in the regex, but I was getting a warning.
There is another question with a similar topic but the match strings are not for objective c.
This is much easier and will accomplish what you want:
NSRange range = [currentItem.summary rangeOfString:#"..."];
if (range != NSNotFound) {
currentItem.summary = [currentItem.summary substringToIndex:range.location];
}
You have forward slashes, /, instead of backward slashes, \, in your pattern. Also if you wish to match everything before the three dots you should use (.*) - tag everything matched by the enclosed .*. (The other parentheses in the pattern are redundant.)
Nice alternative:
NSScanner *scanner = [NSScanner scannerWithString:currentItem.summary];
[scanner scanUpToString:#"..." intoString: ¤tItem.summary];
My recommended regex for your problem:
regularExpressionWithPattern:#"^(.*)\\s*\\.{3}.*$"
Main differences between this one and yours:
uses backslashes to escape special chars
uses ^ and $ to anchor at the beginning and end of the string
only captures the interesting section with ()
strips whitespace before the ... by ignoring any number of whitespace chars (\s*).
After correcting the slashes and other improvements, my final expression is:
NSRegularExpression *regex = [NSRegularExpression regularExpressionWithPattern:#"^(.*)\\.{3}.*$"
options:0
error:&error];
I have a string for example #"You've earned Commentator and 4 ##other$$ badges". I want to retreive the substring #"other", which is delimited by ## and $$. I made a NSRegularExpression like this:
NSRegularExpression *regex = [NSRegularExpression regularExpressionWithPattern:#"##(.*)$$" options:NSRegularExpressionCaseInsensitive error:nil];
This completely ignores $$ and returns stuff starting with ##. What am I doing wrong? thanks.
Thats because '$' is a special character that represents the end of the line. Try \$\$ to escape it and tell the parser you want the characters.
I wouldn't use a regex in this situation, since the string bashing is so simple. No need for the overhead of compiling the expression.
NSString *source = #"You've earned Commentator and 4 ##other$$ badges";
NSRange firstDelimiterRange = [source rangeOfString:#"##"];
NSRange secondDelimiterRange = [source rangeOfString:#"$$"];
NSString *result = [source substringWithRange:
NSMakeRange(firstDelimiterRange.origin +2,
firstDelimiterRange.origin - secondDelimiterRange.origin)];