I need to parse a URL in the following format:
http://www.example.com/?method=example.method&firstKey=firstValue&id=1893736&thirdKey=thirdValue
All I need is the value of 1893736 within &id=1893736.
I need to do the parsing in Objective-C for my iPhone project. I understand it must have something to do with regular expression. But I just have no clue how to do it.
Any suggestions would be appreciated. :)
You don't need a regex for this. You can try something like this
NSString *url = #"http://www.example.com/?method=example.method&firstKey=firstValue&id=1893736&thirdKey=thirdValue";
NSString *identifier = nil;
for (NSString *arg in [[[url pathComponents] lastObject] componentsSeparatedByString:#"&"]) {
if ([arg hasPrefix:#"id="]) {
identifier = [arg stringByReplacingOccurrencesOfString:#"id=" withString:#""];
}
}
NSLog(#"%#", identifier);
Don't use regular expressions. Use NSURL to reliably extract the query string and then use this answer's code to parse the query string.
Use this:
.*/\?(?:\w*=[^&]*&)*?(?:id=([^&]*))(?:&\w*=[^&]*)*
And grap first group: \1. You will obtain 1893736.
Simplifying
If the id can consist of only digits:
.*/\?(?:\w*=[^&]*&)*?(?:id=(\d*))(?:&\w*=[^&]*)*
If you don't care about capturing uninterested groups (use \3 or id in this case):
.*/\?(\w*=.*?&)*?(id=(?<id>\d*))(&\w*=.*)*
More simpler version (use \3):
.*/\?(.*?=.*?&)*(id=(\d*))(&.*?=.*)*
Instead of using regex, you can split the string representation of your NSURL instance. In your case, you can split the string by the appersand (&), loop the array looking for the prefix (id=), and get the substring from the index 2 (which is where the = ends).
Related
I wants to remove specific characters or group substring from NSString.
mean
NSString *str = #" hello I am #39;doing Parsing So $#39;I get many symbols in &my response";
I wants remove #39; and $#39; and & (Mostly these three strings comes in response)
output should be : hello I am doing Parsing So i get many symbols in my response
Side Question : I can't write & #39; without space here, because it converted in ' <-- this symbol. so i use $ in place of & in my question.
you should use [str stringByReplacingOccurrencesOfString:#"#39" withString:#""]
or you need replace strings of concrete format like "#number"?
try below code ,i think you got whatever you want simply change the charecterset,
NSString *string = #"hello I am #39;doing Parsing So $#39;I get many symbols in &my response";
NSCharacterSet *trim = [NSCharacterSet characterSetWithCharactersInString:#"#39;$&"];
NSString *result = [[string componentsSeparatedByCharactersInSet:trim] componentsJoinedByString:#""];
NSLog(#"%#", result);
I have a string in iphone that looks like the following one:
my.whatever.string.with.unknown.length=something whatever something = something .... = whatever
I want to replace only the FIRST "=" with something else.
If I use :
[myString stringByReplacingOccurrencesOfString:#"=" withString:#"somethingHere" ];
It will replace all occurences of "=" . Any suggestions on how to achieve this?
You can use the range argument to specify how far into the string you want it to search. Assuming you can find where the first = is, you can use that to do it. The method definition looks like this:
replaceOccurrencesOfString:withString:options:range:
You can replace string like this..
NSString *mystring=FIRST;
NSString *trimmedString = [mystring stringByReplacingOccurrencesOfString:#" " withString:#""];
I want to check whether a string contains any of the substrings that I place in an array. Basically, I want to search the extensions of a file, and if the file is an "image", i want certain code to execute. The only way I can think of categorizing the file as an "Image" without downloading the file is through the substring in a string method. This is my code so far:
NSString *last5Chars = [folderName substringFromIndex: [folderName length] - 5];
NSRange textRangepdf;
textRangepdf =[last5Chars rangeOfString:#"pdf"];
if(textRangepdf.location != NSNotFound)
{
[self.itemType addObject:#"PDF.png"];
}
Is it possible to do this where I can check if last5Chars contains #"jpg" or #"gif" of #"png" etc...?? Thanks for helping!
NSString *fileName;
NSArray *imgExtArray; // put your file extensions in here
BOOL isImage = [imgExtArray containsObject:[fileName pathExtension]];
[folderName hasSuffix:#".jpg"] || [folderName hasSuffix:#".gif"]
obviously you can put it into a loop, if you have a whole arrayful.
Rather than mess about with ranges and suffixes, NSString has a method that treats an NSString as a path and returns an extension, it's called pathExtension.
Have a look in the NSString Documentation
Once you get the extension you can check it against whatever strings you want.
I have an NSString with a number of sentences, and I'd like to split it into an NSArray of sentences. Has anybody solved this problem before? I found enumerateSubstringsInRange:options:usingBlock: which is able to do it, but it looks like it isn't available on the iPhone (Snow Leopard only). I thought about splitting the string based on periods, but that doesn't seem very robust.
So far my best option seems to be to use RegexKitLite to regex it into an array of sentences. Solutions?
Use CFStringTokenizer. You'll want to create the tokenizer with the kCFStringTokenizerUnitSentence option.
I would use a scanner for it,
NSScanner *sherLock = [NSCanner scannerWithString:yourString]; // autoreleased
NSMutableArray *theArray = [NSMutableArray array]; // autoreleased
while( ![sherLock isAtEnd] ){
NSString *sentence = #"";
// . + a space, your sentences probably will have that, and you
// could try scanning for a newline \n but iam not sure your sentences
// are seperated by it
[sherLock scanUpToString:#". " inToString:&sentence];
[theArray addObject:sentence];
}
This should do it, there could be some little mistakes in it but this is how I would do it.
You should lookup NSScanner in the docs though.. you might come across a method that is
better for this situation.
I haven't used them for a while but I think you can do this with NSString, NSCharacterSet and NSScanner. You create a character set that holds end sentence punctuation and then call -[NSScanner scanUpToCharactersFromSet:intoString:]. Each Scan will suck out a sentence into a string and you keep calling the method until the scanner runs out of string.
Of course, the text has to be well punctuated.
How about:
NSArray *sentences = [string componentsSeparatedByString:#". "];
This will return an array("One","Two","Three") from a string "One. Two. Three."
NSArray *sentences = [astring componentsSeparatedByCharactersInSet:[NSCharacterSet punctuationCharacterSet] ];
Does anyone know a nice efficient way of finding a string within a string (if it exists) in objective c for iPhone Development, I need to find the part of the string in between two words, e.g. here I need to find the co2 rating number in the string, where z is the value I'm looking for ...
xxxxxco_2zendxxxxxxx
Ideally, I'd use a regular expression for this, probably something like co_2(.*?)end, so I'd take a look at RegexKitLite as stimms suggests.
If that is not suitable, you could extract the string you're looking for with something like this:
NSString* src = #"xxxxxco_2zendxxxxxxx";
NSRange startMarker = [src rangeOfString:#"co_2"];
if (startMarker.location != NSNotFound) {
NSScanner* scanner = [NSScanner scannerWithString:src];
[scanner setScanLocation:startMarker.location + startMarker.length];
NSString* co2Value = #"";
[scanner scanUpToString:#"end" intoString:&co2Value];
NSLog(#"co_2 value is %#", co2Value);
} else {
NSLog(#"co_2 marker not found");
}
Here we look for #"co_2", failing if it's not found, then use an NSScanner to grab everything from just after that string to the next occurrence of #"end". Note that if #"end" is missing this code will silently grab the rest of the string.
This might be of interest to you (in particular the rangeOfString function):
(NSRange)rangeOfString:(NSString *)aString
Unfortunately Cocoa doesn't have any built-in RegEx support..
String matching is a well explored domain especially for algorithms dealing with genetic material. You could check out the Art of Computer programming for 10x more than you ever wanted to know about string matching.
Most of that is overkill and you would be fine using a regular expression. Check out http://regexkit.sourceforge.net/RegexKitLite/ a regex library which runs on the iphone.