Check for String within a String - xcode

Question

I'm trying to compare two strings
NSString strOne = #"Cat, Dog, Cow";
NSString strTwo = #"Cow";
How do I determine if strOne contains strTwo

Answer 1

Try using rangeOfString:
NSRange result = [strOne rangeOfString:strTwo];
From the documentation:
Returns an NSRange structure giving the location and length in the receiver of the first occurrence of aString. Returns {NSNotFound, 0} if aString is not found or is empty (#"").

Answer 2

For anyone needing the code to check is a string exists within a string, here's my code thanks to fbrereto. This example checks to see if any string contained in an array of strings (stringArray) can be found within a string (myString):
int count = [stringArray count];
for (NSUInteger x = 0; x < count; ++x) {
NSRange range = [self.myString rangeOfString:[stringArray objectAtIndex:x]];
if (range.length > 0) {
// A match has been found
NSLog(#"string match: %#",[stringArray objectAtIndex:x]);
}
}

Answer 3

I believe this is the correct syntax for checking if the range exists (correcting response from Kendall):
range.location != NSNotFound

Answer 4

Gradually straying off topic, but I always explode my strings, which would mean just exploding it using your search string as a key and you can use the array count to see how many instances you have.
Just incase anyone is coming from a code language that uses "explode" to blow a string up into an array like me, I found writing my own explode function tremendously helpful, those not using "explode" are missing out:
- (NSMutableArray *) explodeString : (NSString *)myString key:(NSString*) myKey
{
NSMutableArray *myArray = [[NSMutableArray alloc] init];
NSRange nextBreak = [myString rangeOfString:myKey];
while(nextBreak.location != NSNotFound)
{
[myArray addObject: [myString substringToIndex:nextBreak.location]];
myString = [myString substringFromIndex:nextBreak.location + nextBreak.length];
nextBreak = [myString rangeOfString:myKey];
}
if(myString.length > 0)
[myArray addObject:myString];
return myArray;
}
works like this:
[self explodeString: #"John Smith|Age: 37|Account Balance: $75.00" key:#"|"];
which will return this array:
[#"John Smith", #"Age: 37", #"Account Balance: $75.00"];
This lets you quickly pull out a specific value in a tight space, Like if you have a client and you want to know how much money he has:
[[self explodeString: clientData key: pipe] objectAtIndex: 1];
or if you wanted specifically the dollar amount as a float:
[[[self explodeString: [[self explodeString: clientData key: pipe] objectAtIndex: 1] key: #": "] objectAtIndex: 2] floatValue];
anyway I find arrays way easier to work with and more flexible, so this is very helpful to me. Additionally with a little effort you could make an "explodable string" data type for your private library that lets you treat it like a string or return an index value based on the key
ExplodableString *myExplodableString;
myExplodableString.string = #"This is an explodable|string";
NSString *secondValue = [myExplodableString useKey: #"|" toGetValue: index];