How can I check if a string (NSString) contains another smaller string?
I was hoping for something like:
NSString *string = @"hello bla bla";
NSLog(@"%d",[string containsSubstring:@"hello"]);
But the closest I could find was:
if ([string rangeOfString:@"hello"] == 0) {
NSLog(@"sub string doesnt exist");
}
else {
NSLog(@"exists");
}
Anyway, is that the best way to find if a string contains another string?
转载于:https://stackoverflow.com/questions/2753956/how-do-i-check-if-a-string-contains-another-string-in-objective-c
NOTE: This answer is now obsolete
Create a category for NSString:
@interface NSString ( SubstringSearch )
- (BOOL)containsString:(NSString *)substring;
@end
// - - - -
@implementation NSString ( SubstringSearch )
- (BOOL)containsString:(NSString *)substring
{
NSRange range = [self rangeOfString : substring];
BOOL found = ( range.location != NSNotFound );
return found;
}
@end
EDIT: Observe Daniel Galasko's comment below regarding naming
NSString *myString = @"hello bla bla";
NSRange rangeValue = [myString rangeOfString:@"hello" options:NSCaseInsensitiveSearch];
if (rangeValue.length > 0)
{
NSLog(@"string contains hello");
}
else
{
NSLog(@"string does not contain hello!");
}
//You can alternatively use following too :
if (rangeValue.location == NSNotFound)
{
NSLog(@"string does not contain hello");
}
else
{
NSLog(@"string contains hello!");
}
Oneliner (Smaller amount of code. DRY, as you have only one NSLog):
NSString *string = @"hello bla bla";
NSLog(@"String %@", ([string rangeOfString:@"bla"].location == NSNotFound) ? @"not found" : @"cotains bla");
An improved version of P i's solution, a category on NSString, that not only will tell, if a string is found within another string, but also takes a range by reference, is:
@interface NSString (Contains)
-(BOOL)containsString: (NSString*)substring
atRange:(NSRange*)range;
-(BOOL)containsString:(NSString *)substring;
@end
@implementation NSString (Contains)
-(BOOL)containsString:(NSString *)substring
atRange:(NSRange *)range{
NSRange r = [self rangeOfString : substring];
BOOL found = ( r.location != NSNotFound );
if (range != NULL) *range = r;
return found;
}
-(BOOL)containsString:(NSString *)substring
{
return [self containsString:substring
atRange:NULL];
}
@end
Use it like:
NSString *string = @"Hello, World!";
//If you only want to ensure a string contains a certain substring
if ([string containsString:@"ello" atRange:NULL]) {
NSLog(@"YES");
}
// Or simply
if ([string containsString:@"ello"]) {
NSLog(@"YES");
}
//If you also want to know substring's range
NSRange range;
if ([string containsString:@"ello" atRange:&range]) {
NSLog(@"%@", NSStringFromRange(range));
}
Here is a copy-and-paste function snippet:
-(BOOL)Contains:(NSString *)StrSearchTerm on:(NSString *)StrText
{
return [StrText rangeOfString:StrSearchTerm
options:NSCaseInsensitiveSearch].location != NSNotFound;
}
Since this seems to be a high-ranking result in Google, I want to add this:
iOS 8 and OS X 10.10 add the containsString: method to NSString. An updated version of Dave DeLong's example for those systems:
NSString *string = @"hello bla bla";
if ([string containsString:@"bla"]) {
NSLog(@"string contains bla!");
} else {
NSLog(@"string does not contain bla");
}
With iOS 8 and Swift, we can use localizedCaseInsensitiveContainsString method
let string: NSString = "Café"
let substring: NSString = "É"
string.localizedCaseInsensitiveContainsString(substring) // true
If you need this once write:
NSString *stringToSearchThrough = @"-rangeOfString method finds and returns the range of the first occurrence of a given string within the receiver.";
BOOL contains = [stringToSearchThrough rangeOfString:@"occurence of a given string"].location != NSNotFound;
If do not bother about case-sensitive string. Try this once.
NSString *string = @"Hello World!";
if([string rangeOfString:@"hello" options:NSCaseInsensitiveSearch].location !=NSNotFound)
{
NSLog(@"found");
}
else
{
NSLog(@"not found");
}
NSString *categoryString = @"Holiday Event";
if([categoryString rangeOfString:@"Holiday"].location == NSNotFound)
{
//categoryString does not contains Holiday
}
else
{
//categoryString contains Holiday
}
Please use this code
NSString *string = @"hello bla bla";
if ([string rangeOfString:@"bla"].location == NSNotFound)
{
NSLog(@"string does not contain bla");
}
else
{
NSLog(@"string contains bla!");
}
So personally I really hate NSNotFound but understand its necessity.
But some people may not understand the complexities of comparing against NSNotFound
For example, this code:
- (BOOL)doesString:(NSString*)string containString:(NSString*)otherString {
if([string rangeOfString:otherString].location != NSNotFound)
return YES;
else
return NO;
}
has its problems:
1) Obviously if otherString = nil this code will crash. a simple test would be:
NSLog(@"does string contain string - %@", [self doesString:@"hey" containString:nil] ? @"YES": @"NO");
results in !! CRASH !!
2) What is not so obvious to someone new to objective-c is that the same code will NOT crash when string = nil. For example, this code:
NSLog(@"does string contain string - %@", [self doesString:nil containString:@"hey"] ? @"YES": @"NO");
and this code:
NSLog(@"does string contain string - %@", [self doesString:nil containString:nil] ? @"YES": @"NO");
will both result in
does string contains string - YES
Which is clearly NOT what you want.
So the better solution that I believe works is to use the fact that rangeOfString returns the length of 0 so then a better more reliable code is this:
- (BOOL)doesString:(NSString*)string containString:(NSString*)otherString {
if(otherString && [string rangeOfString:otherString].length)
return YES;
else
return NO;
}
OR SIMPLY:
- (BOOL)doesString:(NSString*)string containString:(NSString*)otherString {
return (otherString && [string rangeOfString:otherString].length);
}
which will for cases 1 and 2 will return
does string contains string - NO
That's my 2 cents ;-)
Please check out my Gist for more helpful code.
try this,
NSString *string = @"test Data";
if ([[string lowercaseString] rangeOfString:@"data"].location == NSNotFound)
{
NSLog(@"string does not contain Data");
}
else
{
NSLog(@"string contains data!");
}
In case of swift, this can be used
let string = "Package #23"
if string.containsString("Package #") {
//String contains substring
}
else {
//String does not contain substring
}
Best solution. As simple as this! If you want to find a word or part of the string. You can use this code. In this example we are going to check if the value of word contains "acter".
NSString *word =@"find a word or character here";
if ([word containsString:@"acter"]){
NSLog(@"It contains acter");
} else {
NSLog (@"It does not contain acter");
}
If certain position of the string is needed, this code comes to place in Swift 3.0:
let string = "This is my string"
let substring = "my"
let position = string.range(of: substring)?.lowerBound
In Swift 4:
let a = "Hello, how are you?"
a.contains("Hello") //will return true
First string contain or not second string,
NSString *first = @"Banana";
NSString *second = @"BananaMilk";
NSRange range = [first rangeOfString:second options:NSCaseInsensitiveSearch];
if (range.length > 0) {
NSLog(@"Detected");
}
else {
NSLog(@"Not detected");
}
Use the option NSCaseInsensitiveSearch with rangeOfString:options:
NSString *me = @"toBe" ;
NSString *target = @"abcdetobe" ;
NSRange range = [target rangeOfString: me options: NSCaseInsensitiveSearch];
NSLog(@"found: %@", (range.location != NSNotFound) ? @"Yes" : @"No");
if (range.location != NSNotFound) {
// your code
}
Output result is found:Yes
The options can be "or'ed" together and include:
NSCaseInsensitiveSearch NSLiteralSearch NSBackwardsSearch and more
SWift 4 And Above
let str = "Hello iam midhun"
if str.contains("iam") {
//contain substring
}
else {
//doesn't contain substring
}