I would like to know whether or not a certain string has a regex.
I wrote the code below which in order to match strings similar to the following:
"A|3|a3\n"
However the code below gets an array of matches. I do not want that as I want to simply understand whether or not my response string matches the criteria given by the regex. Any suggestion on how to do so?
NSString * response = "A|3|a3\n";
NSRange searchedRange = NSMakeRange(0, [ response length]);
NSString *pattern = #"[ABC]\|[0-9]\|[a][0-9]$";
NSError *error = nil;
NSRegularExpression* regex = [NSRegularExpression regularExpressionWithPattern: pattern options:0 error:&error];
NSArray* matches = [regex matchesInString:response options:0 range: searchedRange];
for (NSTextCheckingResult* match in matches){
NSString* matchText = [response substringWithRange:[match range]];
NSLog(#"match: %#", matchText);
}
Xcode should throw an warning:
Warning: Unknown escape sequence '\|'
for this line:
NSString *pattern = #"[ABC]\|[0-9]\|[a][0-9]$";
"\" escape indeed the next character (to some special signification, like the classical "\n"), but "\|" is a unknown escape sequence for a normal string. So you have to "double it":
NSString *pattern = #"[ABC]\\|[0-9]\\|[a][0-9]$"
I think you are looking for a kind of an IsMatch() function. Here is an example:
NSRange matchRange = [regex rangeOfFirstMatchInString:response options:NSMatchingReportProgress range:searchedRange];
BOOL isFound = NO;
// Did we find a matching range
if (matchRange.location != NSNotFound)
isFound = YES;
Related
I have an NSString which I am checking if there is an NSLog and then I comment it out.
I am using NSRegularExpression and then looping through result.
The code:
-(NSString*)commentNSLogFromLine:(NSString*)lineStr {
NSString *regexStr =#"NSLog\\(.*\\)[\\s]*\\;";
NSRegularExpression *regex = [NSRegularExpression regularExpressionWithPattern:regexStr options:NSRegularExpressionCaseInsensitive error:nil];
NSArray *arrayOfAllMatches = [regex matchesInString:lineStr options:0 range:NSMakeRange(0, [lineStr length])];
NSMutableString *mutStr = [[NSMutableString alloc]initWithString:lineStr];
for (NSTextCheckingResult *textCheck in arrayOfAllMatches) {
if (textCheck) {
NSRange matchRange = [textCheck range];
NSString *strToReplace = [lineStr substringWithRange:matchRange];
NSString *commentedStr = [NSString stringWithFormat:#"/*%#*/",[lineStr substringWithRange:matchRange]];
[mutStr replaceOccurrencesOfString:strToReplace withString:commentedStr options:NSCaseInsensitiveSearch range:matchRange];
NSRange rOriginal = [mutStr rangeOfString:#"NSLog("];
if (NSNotFound != rOriginal.location) {
[mutStr replaceOccurrencesOfString:#"NSLog(" withString:#"DSLog(" options:NSCaseInsensitiveSearch range:rOriginal];
}
}
}
return [NSString stringWithString:mutStr];
}
The problem is with the test case:
NSString *str = #"NSLog(#"A string"); NSLog(#"A string2")"
Instead of returning "/*DSLog(#"A string");*/ /*DSLog(#"A string2")*/" it returns: "/*DSLog(#"A string"); NSLog(#"A string2")*/".
The issue is how the Objective-C handles the regular expression. I would expected 2 results in arrayOfAllMatches but instead that I am getting only one. Is there any way to ask Objective-C to stop on the first occurrence of ); ?
The problem is with the regular expression. You are searching for .* inside the parentheses, which causes it to include the first close parenthesis, continue through the second NSLog statement, and go all the way to the final close parentheses.
So what you want to do is something like this:
NSString *regexStr =#"NSLog\\([^\\)]*\\)[\\s]*\\;";
That tells it to include everything inside the parenthesis except for the ) character. Using that regex, I get two matches. (note that you omitted the final ; in your string sample).
For example , the following is the source I want match:
<div class="cont">
I use
<div\s+class\=\"cont\">
But it doesn't work , if I modify the expression like
<div\s+class\=.*?cont.*?>
Now , it can give me the result I want .
So I think , the problem should be in " this character.
Following is the code I use in iOS , it can works for some other regular expression:
NSRegularExpression *regex = [NSRegularExpression regularExpressionWithPattern:reg options:NSRegularExpressionCaseInsensitive error:nil];
NSArray *matches = [regex matchesInString:resultStr options:0 range:NSMakeRange(0, [resultStr length])];
for (NSTextCheckingResult *match in matches) {
NSRange matchRange = [match range];
NSString *tagString = [resultStr substringWithRange:matchRange];
[resultArr addObject:tagString];
}
You are trying to match HTML with regular expressions. It is definitely very troublesome, since HTML you receive can be all uppercase, single quotes may be used instead of double or be missing, etc.
That said, if you really need a regex solution, I'd recommend to account for any number of attributes before class=cont and allow any attribute value delimiters:
NSString *pattern = #"<div\\b[^<]*class=[\"']?cont\\b[^<]*>";
Here, I am using \b to match a word boundary, [^<]* checks for any other attributes before class, ["']? allows either a single or double quotation mark or nothing, then \b makes sure cont is followed by a non-word character, and [^<]* checks for any other attributes before final >.
Also, \" is escaped once as it is a C string delimiter and \\b is escaped twice to make sure we pass \b to the regex engine.
Sample code at CodingGround:
#import <Foundation/Foundation.h>
#import <Foundation/NSTextCheckingResult.h>
int main (int argc, const char * argv[])
{
NSAutoreleasePool * pool = [[NSAutoreleasePool alloc] init];
NSError *error = nil;
NSString *pattern = #"<div\\b[^<]*class=[\"']?cont\\b[^<]*>";
NSString *string = #"<div class=\"cont\">";
NSRange range = NSMakeRange(0, string.length);
NSRegularExpression *regex = [NSRegularExpression regularExpressionWithPattern:pattern options:0 error:&error];
NSArray *matches = [regex matchesInString:string options:0 range:range];
for (NSTextCheckingResult *match in matches) {
NSRange matchRange = [match range];
NSString *m = [string substringWithRange:matchRange];
NSLog(#"Matched string: %#", m);
}
[pool drain];
return 0;
}
Here goes the code:
NSString *stricterFilterString = #"[A-Z0-9a-z\\._%+-]+#([A-Za-z0-9-]+\\.)+[A-Za-z]{2,4}";
NSString *laxString = #".+#([A-Za-z0-9]+\\.)+[A-Za-z]{2}[A-Za-z]*";
NSString *emailRegex = stricterFilter ? stricterFilterString : laxString;
NSPredicate *emailTest = [NSPredicate predicateWithFormat:#"SELF MATCHES %#", emailRegex];
I'm using a simple pattern with NSRegularExpression to delimit content within a string:
(\s)+(and|or)(\s)+
So, when I use matchesInString it's not the matches that I'm interested in, but the other stuff.
Below is the code that I'm using. Iterating over the matches and then using indexes and lengths to pull out the content.
Question: I'm just wondering if I'm missing something in the api to get the other bits? Or, is the approach below generally ok?
- (NSArray*)separateText:(NSString*)text
{
NSString* regExPattern = #"(\\s)+(and|or)(\\s)+";
NSError* error = NULL;
NSRegularExpression* regex = [NSRegularExpression regularExpressionWithPattern:regExPattern
options:NSRegularExpressionCaseInsensitive
error:&error];
NSArray* matches = [regex matchesInString:text options:0 range:NSMakeRange(0, text.length)];
if (matches.count == 0) {
return #[text];
}
NSInteger itemStartIndex = 0;
NSMutableArray* result = [NSMutableArray new];
for (NSTextCheckingResult* match in matches) {
NSRange matchRange = [match range];
if (!matchRange.location == 0) {
NSInteger matchStartIndex = matchRange.location;
NSInteger length = matchStartIndex - itemStartIndex;
NSString* item = [text substringWithRange:NSMakeRange(itemStartIndex, length)];
if (item.length != 0) {
[result addObject:item];
}
}
itemStartIndex = NSMaxRange(matchRange);
}
if (itemStartIndex != text.length) {
NSInteger length = text.length - itemStartIndex;
NSString* item = [text substringWithRange:NSMakeRange(itemStartIndex, length)];
[result addObject:item];
}
return result;
}
You can capture the string before the and|or with parentheses, and add it to your array with rangeAtIndex.
NSRegularExpression *regex = [NSRegularExpression regularExpressionWithPattern:#"(.+?)(\\s+(and|or)\\W+|\\s*$)" options:NSRegularExpressionCaseInsensitive error:&error];
NSMutableArray *phrases = [NSMutableArray array];
[regex enumerateMatchesInString:string options:0 range:NSMakeRange(0, [string length]) usingBlock:^(NSTextCheckingResult *result, NSMatchingFlags flags, BOOL *stop) {
NSRange range = [result rangeAtIndex:1];
[phrases addObject:[string substringWithRange:range]];
}];
A couple of minor points about my regex:
I added the |\\s*$ construct to capture the last string after the final and|or. If you don't want that, you can eliminate that.
I replaced the second \\s+ (whitespace) with a \\W+ (non-word characters), in case you encountered something like and|or followed by a comma or something else. You could alternatively look explicitly for ,?\\s+ if the comma was the only non-word character you cared about. It just depends upon the specific business problem you're solving.
You might want to replace the first \\s+ with \\W+, too.
If your string contains newline characters, you might want to use the NSRegularExpressionDotMatchesLineSeparators option when you instantiate the NSRegularExpression.
You could replace all matches of the regex with a template string (e.g. ", " or "," etc) and then separate the string components based on that new delimiter.
NSString *stringToBeMatched = #"Your string to be matched";
NSString *regExPattern = #"(\\s)+(and|or)(\\s)+";
NSError *error = nil;
NSRegularExpression *regex = [NSRegularExpression regularExpressionWithPattern:regExPattern
options:NSRegularExpressionCaseInsensitive
error:&error];
if (error) {
// handle error
}
NSString *replacementString = [regex stringByReplacingMatchesInString:stringToBeMatched
options:0
range:NSMakeRange(0, stringToBeMatched.length)
withTemplate:#","];
NSArray *otherItemsInString = [replacementString componentsSeparatedByString:#","];
I have an NSString as:
"<a href='javascript:void(null)' onclick='handleCommandForAnchor(this, 10);return false;'>12321<\/a>"
I need to extract the 12321 near the end of the NSString from it and store.
First I tried
NSString *shipNumHtml=[mValues objectAtIndex:1];
NSInteger htmlLen=[shipNumHtml length];
NSString *shipNum=[[shipNumHtml substringFromIndex:htmlLen-12]substringToIndex:8];
But then I found out that number 12321 can be of variable length.
I can't find a method like java's indexOf() to find the '>' and '<' and then find substring with those indices. All the answers I've found on SO either know what substring to search for or know the location if the substring. Any help?
I don't usually advocate using Regular expressions for parsing HTML contents but it seems a regex matching >(\d+)< would to the job in this simple string.
Here is a simple example:
NSError *error = nil;
NSRegularExpression *regex = [NSRegularExpression regularExpressionWithPattern:#">(\\d+)<"
options:0
error:&error];
// Handle error != nil
NSTextCheckingResult *match = [regex firstMatchInString:string
options:0
range:NSMakeRange(0, [string length])];
if (match) {
NSRange matchRange = [match rangeAtIndex:1];
NSString *number = [string substringWithRange:matchRange]
NSLog(#"Number: %#", number);
}
As #HaneTV says, you can use the NSString method rangeOfString to search for substrings. Given that the characters ">" and "<" appear in multiple places in your string, so you might want to take a look at NSRegularExpression and/or NSScanner.
that may help on you a bit, I've just tested:
NSString *_string = #"<a href='javascript:void(null)' onclick='handleCommandForAnchor(this, 10);return false;'>12321</a>";
NSError *_error;
NSRegularExpression *_regExp = [NSRegularExpression regularExpressionWithPattern:#">(.*)<" options:NSRegularExpressionCaseInsensitive error:&_error];
NSArray *_matchesInString = [_regExp matchesInString:_string options:NSMatchingReportCompletion range:NSMakeRange(0, _string.length)];
[_matchesInString enumerateObjectsUsingBlock:^(NSTextCheckingResult * result, NSUInteger idx, BOOL *stop) {
for (int i = 0; i < result.numberOfRanges; i++) {
NSString *_match = [_string substringWithRange:[result rangeAtIndex:i]];
NSLog(#"%#", _match);
}
}];
I have a following string in iOS :-
[{"status":"0","eventid":"126"}]15.511563,73.809732[{"status":"0"}]
And I am trying to fetch this :-
[{"status":"0","eventid":"126"}]
i.e. the entire portion of string before first ] closing bracket.
I tried this in which I get a substring of 31 characters, but this won't work if the contents between the brackets changes.
NSRange start = [result1 rangeOfString:#"["];
NSString *shortString =[result1 substringWithRange:NSMakeRange(start.location, 31)];
result1 = [result1 substringToIndex:shortString.length];
NSLog(#"Response- %#",result1);
What is the correct approach?
Just like you are getting the start range (NSRange start = [result1 rangeOfString:#"["];), also get the end range:
NSRange end = [result1 rangeOfString:#"]"];
Now you have enough information to extract the substring:
NSString *result = [result1 substringWithRange:NSMakeRange(start.location, end.location - start.location)];
In your current code, you don't need to use substring... methods twice as you have already extracted the string you want in the first call. Making the second call is just ignoring the bit of code which found the start location and assuming that you always want the substring from the start of the string, which is less flexible.
Make the END Range also
NSRange start;
NSRange end;
start = [result1 rangeOfString: #"["];
end = [result1 rangeOfString: #"]"];
NSString *newResult = [result1 substringWithRange:NSMakeRange(start.location+1, end.location)];
NSLog(#"%#", newResult);
You could try using a NSRegularExpression:
NSError *error = NULL;
NSRegularExpression *regex =
[NSRegularExpression regularExpressionWithPattern:#"\\[(.*?)\\]"
options:NSRegularExpressionCaseInsensitive
error:&error];
Now, search for the first match:
NSString *string = #"[{\"status\":\"0\",\"eventid\":\"126\"}]15.511563,73.809732[{\"status\":\"0\"}]";
NSTextCheckingResult *match =
[regex firstMatchInString:string
options:0
range:NSMakeRange(0, [string length])];
Now you can get the range for the capture group:
NSRange block = [match rangeAtIndex:1];