I need to search the index of a string from NSMutableArray. I have implemented the code & which works perfect, but I need to increase the searching speed than this.
I have used the following code:
NSIndexSet *indexes = [mArrayTableData indexesOfObjectsPassingTest:^BOOL(id obj, NSUInteger idx, BOOL *stop){
NSString *s = (NSString*)obj;
NSRange range = [s rangeOfString: txtField.text options:NSCaseInsensitiveSearch];
if(range.location == 0)//
return range.location != NSNotFound;
return NO;
}];
NSLog(#"indexes.firstIndex =%d",indexes.firstIndex);
There is a method indexOfObject
NSString *yourString=#"Your string";
NSMutableArray *arrayOfStrings = [NSMutableArray arrayWithObjects: #"Another strings", #"Your string", #"My String", nil];
NSInteger index=[arrayOfStrings indexOfObject:yourString];
if(NSNotFound == index) {
NSLog(#"Not Found");
}
If you only want one index (or just the first one if there are multiples), you can use the singular version of the method you posted. You also don't need the if clause:
NSInteger index = [mArrayTableData indexOfObjectPassingTest:^BOOL(NSString *obj, NSUInteger idx, BOOL *stop){
return [obj.lowercaseString isEqualToString:txtField.text.lowercaseString];
}];
If you want to find strings that start with the search string, just replace isEqualToString: with hasPrefix:. With a large search set, this appears to be about twice as fast as the method you posted.
Related
My Problem Scenario is like this. I have an NSMutableArray ( Every Object is Nsstring). I have a UItextField ( as Client said) for Search.
I want know how to Search String into NSMutableArray like this
if I type A into textfield only those Content come from NSMutableArray which start From A.
if I type AB into TextField only those Content Comes from NSMutableArray which is started from AB..
....
I am Trying NSRange Concept I like share Mycode
~
for (int i=0; i<[[localTotalArrayForAwailable objectForKey:#"PUNCH"] count]; i++)
{
NSString *drinkNamePuch= [[[localTotalArrayForAwailable objectForKey:#"PUNCH"] objectAtIndex:i] drinkNames];
NSRange titleResultsRange = [drinkNamePuch rangeOfString:searchText options:( NSCaseInsensitiveSearch)];
if (titleResultsRange.length>0)
{
[searchArraypuch addObject:[[localTotalArrayForAwailable objectForKey:#"PUNCH"] objectAtIndex:i]];
[copyListOfItems setValue:searchArraypuch forKey:#"PUNCH"];
}
}
~
Based on this code search not working proper as i need.
Thanks
If you're trying to find all of the strings that match your searchText from the beginning, then you should check:
if ( titleresultsRange.location == 0 )
Other than that, I am not sure what is "not working proper", you need to provide a better explanation of what your expected results are, and what your actual results are.
Do this;
NSPredicate* predicate = [NSPredicate predicateWithFormat:#"SELF BEGINSWITH[cd] %#", searchText];
NSArray* filteredStrings = [[localTotalArrayForAwailable objectForKey:#"PUNCH"] filteredArrayUsingPredicate:predicate];
In filteredStrings you got all the strings that begins with searchText.
You might find Predicate Programming Guide helpful.
try this logic....it is working
NSMutableArray *arr = [[NSMutableArray alloc]initWithObjects:#"aa",#"bbb",#"bb",#"cc",#"dd",#"ee",#"ff",#"gg",#"hh",#"ii", nil];
NSMutableArray *arrNew = [[NSMutableArray alloc]init];
NSString *strSearch = #"cccc";
int k = strSearch.length;
for (int i=0; i<[arr count]; i++) {
for (int j=0; j<k; j++) {
if (k<=[[arr objectAtIndex:i] length]) {
if ([strSearch characterAtIndex:j] != [[arr objectAtIndex:i]characterAtIndex:j]) {
break;
}
else if(j == k-1){
[arrNew addObject:[arr objectAtIndex:i]];
}
}
}
}
NSLog(#"%#",[arrNew description]);
You can use these methods, which are provided by NSArray/NSMutableArray:
In NSArray see section "Finding Objects in an Array" for filtering methods starting with "indexesOfObjects...", e.g. indexesOfObjectsPassingTest:
In NSArray see section "Deriving New Arrays" for the method filteredArrayUsingPredicate:
In NSMutableArray there is a method filterUsingPredicate:
For narrowing the results you can continue applying the filtering consecutively to the filtered arrays or index sets.
Example with indexesOfObjectsPassingTest: using a block:
NSArray *strings = [NSArray arrayWithObjects:#"A", #"a", #"aB", #"AbC", #"Bag", #"Babc", #"baCK", #"", #"dba", nil];
NSString *searchString = #"Ab";
BOOL (^startsWithPredicate)(id, NSUInteger, BOOL*) = ^BOOL (id obj, NSUInteger idx, BOOL *stop) {
NSString *string = (NSString *) obj;
NSRange range = [string rangeOfString:searchString options:NSCaseInsensitiveSearch];
return (range.location == 0);
};
NSIndexSet *indexSet = [strings indexesOfObjectsPassingTest:startsWithPredicate];
NSLog(#"Strings found: %#", [strings objectsAtIndexes:indexSet]);
Output:
Strings found: (
aB,
AbC
)
I am having an array like fallowing,
NSArray*array = [NSArray arrayWithObjects:#"1.1 something", #"1.2 something else", #"1.3 out of left field", #"1.4 yet another!", nil];
Now,i am having the string like fallowing,
NSString*str = #"1.3";
Now i will send the str .Then it needs to find that str in array and it need to return the index of object where that text found.Means i need index 2 has to come as output.Can anyone share the code please.Thanks in advance.
Here is an example using blocks, notice the method: hasPrefix:
NSArray *array = [NSArray arrayWithObjects:#"1.1 problem1", #"1.2 problem2", #"1.3 problem3", #"1.4 problem4", nil];
NSString *str = #"1.3";
NSUInteger index = [array indexOfObjectPassingTest:
^(id obj, NSUInteger idx, BOOL *stop) {
return [obj hasPrefix:str];
}];
NSLog(#"index: %lu", index);
NSLog output:
index: 2
First a comment,
NSString *str = 1.3;
does not create an NSString object. You should instead have
NSString *str = #"1.3";
To search the NSArray, you will either have to change the string to the exact string in the array or search the NSString as well. For the former, simply do
float num = 1.3;
NSString *str = [NSString stringWithFormat:#"%.1f problem%d",num,(num*10)%10];
[array indexOfObject:str];
You can get fancier using NSPredicates as well.
Try
NSString *searchString = [str stringByAppendingFormat: #" problem%#", [str substringFromIndex: 2]];
NSUInteger index = [array indexOfObject: searchString];
Or (because you somehow like oneliners):
[array indexOfObject: [[array filteredArrayUsingPredicate: [NSPredicate predicateWithFormat: #"SELF beginswith %#", str]] objectAtIndex: 0]];
The simplest way is to enumerate through values of array and check substrings:
NSArray *array = [NSArray arrayWithObjects: #"1.1 something", #"1.2 something else", #"1.3 out of left field", #"1.4 yet another!", nil];
NSString *str = #"1.33";
int i = -1;
int index = -1;
for (NSString *arrayString in array) {
i++;
if ([arrayString rangeOfString: str].location != NSNotFound) {
index = i;
break;
}
}
NSLog(#"Index: %d", index);
Not optimal but will work.
I would know how retrieve an index of an NSArray using a NSPredicate ?
NSArray *array = [NSArray arrayWithObjects:
#"New-York City",
#"Washington DC",
#"Los Angeles",
#"Detroit",
nil];
Which kind of method should I use in order to get the index of "Los Angles" by giving only a NSString?
NB: #"Los An" or #"geles" should return the same index.
Using NSPredicate you can get array of strings that contain your search string (it seems there's no built-in method to get just element indexes):
NSPredicate *predicate = [NSPredicate predicateWithFormat:#"SELF CONTAINS[cd] %#", searchString];
NSArray *filteredArray = [array filteredArrayUsingPredicate: predicate];
You can get only indexes using indexesOfObjectsPassingTest: method:
NSIndexSet *indexes = [array indexesOfObjectsPassingTest:^BOOL(id obj, NSUInteger idx, BOOL *stop){
NSString *s = (NSString*)obj;
NSRange range = [s rangeOfString: searchString];
return range.location != NSNotFound;
}];
If you want to get just one element containing your string you can use similar indexOfObjectPassingTest: method for that.
You should be able to do this with blocks. Below is a snippet (I don't have a compiler handy so pls excuse any typos):
NSArray *array = [NSArray arrayWithObjects:
#"New-York City",
#"Washington DC",
#"Los Angeles",
#"Detroit",
nil];
NSString *matchCity = #"Los";
NSPredicate *predicate = [NSPredicate predicateWithFormat:#"SELF contains[cd] %#", matchCity];
NSUInteger index = [self.array indexOfObjectPassingTest:^(id obj, NSUInteger idx, BOOL *stop) {
return [predicate evaluateWithObject:obj];
}];
Essentially you can use the indexOfObjectPassingTest: method. This takes a block (code following the "^") and returns the index for the first object that matches your predicate (or NSNotFound if no match exists). The block iterates through each object in the array until either a match is found (at which point it returns the index) or no match is found (at which point it returns NSNotFound). Here is a link to block programming that can help you understand the logic within the block:
https://developer.apple.com/library/ios/featuredarticles/Short_Practical_Guide_Blocks/
Found an alternative approach helpful where the search is more complex as it allows predicate to be used to find object then object to find index:
-(NSIndexPath*) indexPathForSelectedCountry{
NSUInteger indexToCountry = 0;
NSPredicate * predicate = [NSPredicate predicateWithFormat:#"isoCode = %#",self.selectedCountry.isoCode];
NSArray * selectedObject = [self.countryList filteredArrayUsingPredicate:predicate];
if (selectedObject){
if (self.searchDisplayController.isActive){
indexToCountry = [self.searchResults indexOfObject:selectedObject[0]];
}else{
indexToCountry = [self.countryList indexOfObject:selectedObject[0]];
}
}
return [NSIndexPath indexPathForRow:indexToCountry inSection:0];
}
I would do this..
NSString * stringToCompare = #"geles";
int foundInIndex;
for ( int i=0; i<[array count]; i++ ){
NSString * tryString = [[array objectAtIndex:i] description];
if ([tryString rangeOfString:stringToCompare].location == NSNotFound) {
// no match
} else {
//match found
foundInIndex = i;
}
}// end for loop
Based on #Louie answer, instead of using for loop i had used enumeration block which worked for me.
I did this :-
NSString *stringToCompare = #"xyz";
[myArray enumerateObjectsUsingBlock:^(id *Obj, NSUInteger idx, BOOL * _Nonnull stop) {
NSString * tryString = [[myArray objectAtIndex:idx] description];
if ([tryString rangeOfString:stringToCompare].location == NSNotFound) {
// no match found
} else {
//match found and perform your operation. In my case i had removed array object at idx
}
}];
I can use [NSArray indexOfObject: NSString] to get an index of my search for 1 item. But what can I use or do to get an array of returned indices from my search?
thanks
To get multiple indices, you can use indexesOfObjectsPassingTest::
// a single element to search for
id target;
// multiple elements to search for
NSArray *targets;
...
// every index of the repeating element 'target'
NSIndexSet *targetIndices = [array indexesOfObjectsPassingTest:^ BOOL (id obj, NSUInteger idx, BOOL *stop) {
return [obj isEqual:target];
}];
// every index of every element of 'targets'
NSIndexSet *targetsIndices = [array indexesOfObjectsPassingTest:^ BOOL (id obj, NSUInteger idx, BOOL *stop) {
return [targets containsObject:obj];
}];
Support for blocks were added in iOS 4. If you need to support earlier versions of iOS, indexesOfObjectsPassingTest: isn't an option. Instead, you can use indexOfObject:inRange: to roll your own method:
#interface NSArray (indexesOfObject)
-(NSIndexSet *)indexesOfObject:(id)target;
#end
#implementation NSArray (indexesOfObject)
-(NSIndexSet *)indexesOfObject:(id)target {
NSRange range = NSMakeRange(0, [self count]);
NSMutableIndexSet *indexes = [[NSMutableIndexSet alloc] init];
NSUInteger idx;
while (range.length && NSNotFound != (idx = [self indexOfObject:target inRange:range])) {
[indexes addIndex: idx];
range.length -= idx + 1 - range.location;
range.location = idx + 1;
}
return [indexes autorelease];
}
#end
If you don't have access to indexOfObjectsPassingTest, as #outis recommends, you could use indexOfObject:inRange: and loop over the results, updating the range to start after the last result finished, and updating the results into your own NSIndexSet, or NSMutableArray, etc.
I'm developing a custom UIViewController for iPhone that emulates a subset of the MPMediaPickerController for files in my application's local documents directory. In particular, I'm attempting to re-create the Songs tab. I've been successful in creating my new controller, except I can't get the song titles to sort like they do in the iPod Library or the MPMediaPickerController. Here's an example of how the song names need to be sorted:
Awesome Song Title
Cool Song
The Darkest Song Ever
My Song Title
A Really Cool Song
Why Me?
4 Hours Wasted
As you can see, the sorting excludes the leading articles in the song titles and also places songs that begin with a numeric value at the end of the list. Can anyone suggest an efficient sorting function that takes these tules into account?
Since it looks like no one could offer up a solution, I thought I would post the solution I came up with. First, I created a model for my data:
#interface MyModel : NSObject
{
NSString* _value;
NSString* _sortableValue;
}
#property (nonatomic,copy) NSString* value;
- (NSString*)sortableValue;
- (NSString*)comparableString:(NSString*)str;
#end
They key to the model is the comparableString method, which gets used to create the sortableValue. Here's the implementation of the model:
#implementation MyModel
#synthesize value=_value;
-(void)dealloc
{
[_value release];
[_sortableValue release];
[super dealloc];
}
- (void)setValue:(NSString*)value
{
[_value release];
_value = [value copy];
[_sortableValue release];
_sortableTValue = nil;
}
- (NSString*)sortableValue
{
if (_sortableValue == nil)
_sortableValue = [[self comparableString:_value] retain];
return _sortableValue;
}
- (NSString*)comparableString:(NSString*)str
{
if (str == nil)
return nil;
else if ([str length] == 0)
return [NSString stringWithString:str];
NSCharacterSet* numbersSet = [NSCharacterSet decimalDigitCharacterSet];
if ([str rangeOfCharacterFromSet:numbersSet options:0 range:NSMakeRange(0, 1)].location != NSNotFound)
return [NSString stringWithString:str];
NSRange range = NSMakeRange(0, [str length]);
if ([str compare:#"a " options:(NSAnchoredSearch|NSCaseInsensitiveSearch) range:NSMakeRange(0, 2)] == NSOrderedSame)
range.location = 2;
else if ([str compare:#"an " options:(NSAnchoredSearch|NSCaseInsensitiveSearch) range:NSMakeRange(0, 3)] == NSOrderedSame)
range.location = 3;
else if ([str compare:#"the " options:(NSAnchoredSearch|NSCaseInsensitiveSearch) range:NSMakeRange(0, 4)] == NSOrderedSame)
range.location = 4;
range.length -= range.location;
NSCharacterSet* lettersSet = [NSCharacterSet letterCharacterSet];
NSUInteger letterOffset = [str rangeOfCharacterFromSet:lettersSet options:0 range:range].location;
if (letterOffset == NSNotFound)
return [NSString stringWithString:str];
letterOffset -= range.location;
range.location += letterOffset;
range.length -= letterOffset;
return [str substringWithRange:range];
}
#end
In addition to the removing the leading articles from the string, it also removes any leading non-letter characters. I have a song in my iPod library entitled "$ell Your $oul", which ends up in the E section in the MPMediaPickerController. I'm not sure that's what I would have done had I crated the initial sorting algorithm, but I was going to consistency with the MPMediaPickerController, so there you go.
The final piece of the puzzle is the UILocalizedIndexedCollation class. This handy little helper class will help you sort your data to make supplying it to a UITableView via a UITableViewDataSource a piece of cake. Here's a snippet on how to use the UILocalizedIndexedCollation class in conjunction with the model:
// tableData will contain an NSArray for each populated section in the table view
NSMutableDictionary* tableData = [NSMutableDictionary dictionary];
NSMutableArray* myArray = [NSMutableArray array];
// Populate myArray with instances of MyModel
UILocalizedIndexedCollation* indexer = [UILocalizedIndexedCollation currentCollation];
for (MyModel* data in myArray)
{
NSInteger index = [indexer sectionForObject:data collationStringSelector:#selector(sortableValue)];
NSNumber* key = [[NSNumber alloc] initWithInteger:index];
NSMutableArray* array = [tableData objectForKey:key];
if (array == nil)
{
array = [NSMutableArray new]; // Will be released after creating a sorted array in the following section
[tableData setObject:array forKey:key];
}
[array addObject:data];
[key release];
}
[tableData enumerateKeysAndObjectsUsingBlock:^(id key, id array, BOOL* stop)
{
NSMutableArray* sortedArray = [[indexer sortedArrayFromArray:array collationStringSelector:#selector(sortableValue)] mutableCopy];
[tableData setObject:sortedArray forKey:key];
[array release];
}];
One quick note about UILocalizedIndexedCollation (from Apple's documentation):
If the application provides a
Localizable.strings file for the
current language preference, the
indexed-collation object localizes
each string returned by the method
identified by selector.
So make sure you provide a Localizable.strings for each language you want to support, or your table view will only have sections A-Z and #.
It took me a while to work out all of the details on this, so I hope it becomes useful for other people. If you see any ways I can improve this, please let me know!
You may need to consider certain characters with accents as well such as è, é, ò, à, ù, ì.
So I slightly modified your code to incorporate this. Your code is a great contribution to all of us iphone developers
- (NSString*)comparableString:(NSString*)str
{
if (str == nil)
return nil;
else if ([str length] == 0)
return [NSString stringWithString:str];
NSCharacterSet* numbersSet = [NSCharacterSet decimalDigitCharacterSet];
if ([str rangeOfCharacterFromSet:numbersSet options:0 range:NSMakeRange(0, 1)].location != NSNotFound)
return [NSString stringWithString:str];
NSRange range = NSMakeRange(0, [str length]);
if ([str compare:#"a " options:(NSAnchoredSearch|NSCaseInsensitiveSearch) range:NSMakeRange(0, 2)] == NSOrderedSame)
range.location = 2;
else if ([str compare:#"an " options:(NSAnchoredSearch|NSCaseInsensitiveSearch) range:NSMakeRange(0, 3)] == NSOrderedSame)
range.location = 3;
else if ([str compare:#"the " options:(NSAnchoredSearch|NSCaseInsensitiveSearch) range:NSMakeRange(0, 4)] == NSOrderedSame)
range.location = 4;
range.length -= range.location;
NSCharacterSet* lettersSet = [NSCharacterSet letterCharacterSet];
NSUInteger letterOffset = [str rangeOfCharacterFromSet:lettersSet options:0 range:range].location;
if (letterOffset == NSNotFound)
return [NSString stringWithString:str];
letterOffset -= range.location;
range.location += letterOffset;
range.length -= letterOffset;
//my modification starts here.........
NSString * finalString = [str substringWithRange:range];
NSString * firstCharString = [finalString substringToIndex:1];
NSData * encodedData = [firstCharString dataUsingEncoding:NSASCIIStringEncoding allowLossyConversion:YES];
NSString * encodedString = [[NSString alloc] initWithBytes:[encodedData bytes] length:[encodedData length] encoding:NSASCIIStringEncoding];
if ([encodedString isEqualToString:#"?"]) {
return finalString;
}
NSString * finalProcessedString = [finalString stringByReplacingCharactersInRange:NSMakeRange(0, 1) withString:encodedString];
[encodedString release];
return finalProcessedString;
}