String Replacement operations in objective c - objective-c

Question

I got the result which is in the form of
<ZmaterialGroupList><Matkl>001</Matkl><Text>Metal processing</Text></ZmaterialGroupList>
I need to get the result as 001 Metal processing when i apply the string replacement function upon this it give an exception.Please help me.
Added code from comment:
for(int i=0; i<[soapArray.items count]; i++) {
NSString *str = [soapArray.items objectAtIndex:i];
str = [str stringByReplacingOccurrencesOfString:#"<Matkl>" withString:#""];
}
In this way I wrote but I got an exception like
Invalid argument pass at str

Answer 1

You might do better to use NSXMLParser rather than trying to replace pieces of the XML.
If you update your question to include a bit more explaining your code (specifically the code that deals with soapArray), I should be able explain a bit more as to why your code doesn't work as it is.
Using NSXMLParser
It's important to remember that NSXMLParser just reads the data you give it sequentially, it doesn't use a DOM structure.
Setup
Primarily you need to give your parser something to parse! In my example I get a resource from the bundle and convert it to NSData. There is also however another option to initWithContentsOfURL. Make sure you don't forget to set your delegate!
-(void) parse
{
NSString *file = #"myXMLFile.xml";
NSData *data = [NSData dataWithContentsOfFile:[[NSBundle mainBundle] pathForResource:[file stringByDeletingPathExtension] ofType:[file pathExtension]]];
//If you already have a string:
//NSData* data=[xmlString dataUsingEncoding:NSUTF8StringEncoding];
if (data.length == 0)
{
//No data
return nil;
}
...
}
NSXMLParser *parser = [[NSXMLParser alloc] initWithData:data];
parser.delegate = self;
[parser parse];
Parsing
-(void) parserDidStartDocument:(NSXMLParser *)parser
{
//Here you set up any variables you might need while parsing
}
-(void) parserDidEndDocument:(NSXMLParser *)parser
{
//I usually don't have to do anything here but you might need to release some variables here for example.
}
-(void) parser:(NSXMLParser *)parser didStartElement:(NSString *)elementName namespaceURI:(NSString *)namespaceURI qualifiedName:(NSString *)qName attributes:(NSDictionary *)attributeDict
{
//Here is where the bulk of the parsing is done if you are using attributes. I prefer to use attributes as it looks cleaner both in the XML file and the parser.
if ([elementName isEqualToString:#"element1"])
{
//Just an example of what you might want to do
int index = [[attributeDict valueForKey:#"attribute1"] intValue];
NSString *name = [attributeDict valueForKey:#"n"];
[exampleDictionary setValue:name forKey:[NSString stringWithFormat:#"%d", index]];
}
if ([elementName isEqualToString:#"element2"])
{
//We need to know that the next piece of information (from foundCharacters) is for element 2
currentElement = ELEMENT_2;
}
}
//If you haven't used attributes you might find that you have a lot of parsing to do here instead.
-(void) parser:(NSXMLParser *)parser foundCharacters:(NSString *)string
{
//Check what this info is for?
if(currentElement == ELEMENT_2)
{
element2Data = [NSString stringWithString:string];
}
}
-(void) parser:(NSXMLParser *)parser didEndElement:(NSString *)elementName namespaceURI:(NSString *)namespaceURI qualifiedName:(NSString *)qName
{
if ([elementName isEqualToString:#"element2"])
{
myObject.somethingThatNeedsElement2 = element2;
}
}
Finishing
After finishing it's a good idea to check that nothing went wrong and free up the parser memory. So in your parse method, add this after the call to [parser parse].
if ([parser parserError] != nil)
{
[[[[UIAlertView alloc] initWithTitle:#"Error parsing XML" message:[[parser parserError] localizedDescription] delegate:nil cancelButtonTitle:#"Done" otherButtonTitles:nil] autorelease] show];
}
[parser release];

Answer 2

Consider using an XML parser or you can use NSScanner:
Example:
NSString *wanted;
NSString *fullMessage;
NSString *xml = #"<ZmaterialGroupList><Matkl>001</Matkl><Text>Metal processing</Text></ZmaterialGroupList>";
NSScanner *scanner = [NSScanner scannerWithString:xml];
[scanner scanUpToString:#"<Matkl>" intoString:nil];
[scanner scanString:#"<Matkl>" intoString:nil];
[scanner scanUpToString:#"</Matkl>" intoString:&wanted];
fullMessage = wanted;
[scanner scanUpToString:#"<Text>" intoString:nil];
[scanner scanString:#"<Text>" intoString:nil];
[scanner scanUpToString:#"</Text>" intoString:&wanted];
fullMessage = [fullMessage stringByAppendingFormat:#" %#", wanted];
NSLog(#"fullMessage: '%#'", fullMessage);
NSLog output:
fullMessage: '001 Metal processing'