I have filled a NSMutableArray with integer and string values from my database.
The problem is that many values were inserted more than once.
Using the following code I remove duplicate objects
for (id object in originalArray) {
if (![singleArray containsObject:object]) {
[singleArray addObject:object];
}
}
Bus this works only if the objects are exactly the same between them.
Is there a way to remove duplicates based on the integer value?
EDIT (from an OP's comment on a deleted answer)
I have some objects containing int and NSString. For example #"John 13", #"Mary 25", #"Luke 25", #"Joan 13". The NSMutableArray will contain all four names and duplicates of 13, 25. I want to remove the duplicates leaving 13 and 25 only once in the array. I do not care which names will be removed. Care only for the integer values to use them later.
If your elements are all NSNumber objects:
for (int i=0;i<array.count;i++) {
for (int j=i+1;j<array.count;j++) {
if ([array[i] isEqualToNumber:array[j]]) {
[array removeObjectAtIndex:j--];
}
}
}
Or if all objects are either integer NSNumbers or NSStrings containing integer values:
for (int i=0;i<array.count;i++) {
for (int j=i+1;j<array.count;j++) {
if ([array[i] intValue] == [array[j] intValue]) {
[array removeObjectAtIndex:j--];
}
}
}
Try this:
// singleArray is initially empty
for (id object in originalArray)
{
BOOL contains= YES;
for( id single in singleArray)
{
if( [single integerValue]==[object integerValue] )
{
contains= NO;
break;
}
}
if(contains)
{
[singleArray addObject: object];
}
}
no test, tell me if it does not work. assuming objects in the array are string and format is "WORD NUMBER"
Boolean myEqual(const void *value1, const void *value2) {
NSString *str1 = (__bridge NSString *)(value1);
NSString *str2 = (__bridge NSString *)(value2);
NSArray *arr1 = [str1 componentsSeparatedByCharactersInSet:[NSCharacterSet whitespaceCharacterSet]];
NSArray *arr2 = [str2 componentsSeparatedByCharactersInSet:[NSCharacterSet whitespaceCharacterSet]];
return [[arr1 lastObject] isEqual:[arr2 lastObject]];
}
CFHashCode myHash(const void *value) {
NSString *str1 = (__bridge NSString *)(value);
NSArray *arr1 = [str1 componentsSeparatedByCharactersInSet:[NSCharacterSet whitespaceCharacterSet]];
return [[arr1 lastObject] hash];
}
NSMutableArray *array = // your array;
CFSetCallBacks callBacks = kCFTypeSetCallBacks;
callBacks.equal = myEqual;
callBacks.hash = myHash;
CFMutableSetRef set = CFSetCreateMutable(NULL, [array count], &callBacks);
for (id obj in [array copy]) { // copy so can modify the original array
if (CFSetContainsValue(set, (__bridge const void *)(obj))) {
[array removeObject:obj];
} else {
CFSetAddValue(set, (__bridge const void *)(obj));
}
}
Related
I have an array of strings from an online database that I trying to determine the most commonly used word. The values inside the arrays will vary but I want to check the most common words of whatever collection or words I'm using. If theoretically I had an array of the following...
NSArray *stringArray = [NSArray arrayWithObjects:#"Duck", #"Duck", #"Duck", #"Duck", #"Goose"];
How do I iterate through this array to determine the most common string, which would obviously be "Duck"?
Simplest way is probably NSCountedSet:
NSCountedSet* stringSet = [[NSCountedSet alloc] initWithArray:strings];
NSString* mostCommon = nil;
NSUInteger highestCount = 0;
for(NSString* string in stringSet) {
NSUInteger count = [stringSet countForObject:string];
if(count > highestCount) {
highestCount = count;
mostCommon = string;
}
}
You can use the word as a key into a dictionary.
NSMutableDictionary *words = [NSMutableDictionary dictionary];
for (NSString *word in stringArray) {
if (!words[word]) {
[words setValue:[NSDecimalNumber zero] forKey:word];
}
words[word] = [words[word] decimalNumberByAdding:[NSDecimalNumber one]];
}
Now iterate through words and find the key with the highest value.
NSString *mostCommon;
NSDecimalNumber *curMax = [NSDecimalNumber zero];
for (NSString *key in [words allKeys]) {
if ([words[key] compare:curMax] == NSOrderedDescending) {
mostCommon = key;
curMax = word[key];
}
}
NSLog(#"Most Common Word: %#", mostCommon);
EDIT: Rather than looping through the array once then looping separately through the sorted dictionary, I think we can do better and do it all in a single loop.
NSString *mostCommon;
NSDecimalNumber *curMax = [NSDecimalNumber zero];
NSMutableDictionary *words = [NSMutableDictionary dictionary];
for (NSString *word in stringArray) {
if (!words[word]) {
[words setValue:[NSDecimalNumber zero] forKey:word];
}
words[word] = [words[word] decimalNumberByAdding:[NSDecimalNumber one]];
if ([words[word] compare:curMax] == NSOrderedDescending) {
mostCommon = word;
curMax = words[word];
}
}
NSLog(#"Most Common Word: %#", mostCommon);
This should be significantly faster than my answer pre-edit, though I don't know how it compares to using the NSCountedSet answer.
Try using NSPredicate.
NSUInteger count=0;
NSString *mostCommonStr;
for(NSString *strValue in stringArray) {
NSUInteger countStr=[[stringArray filteredArrayUsingPredicate:[NSPredicate predicateWithFormat:#"self MATCHES[CD] %#, strValue]]count];
if(countStr > count) {
count=countStr;
mostCommonStr=strValue;
}
}
NSLog(#"The most commonstr is %#",mostCommonStr);
after a decent search and could not find solution (probably i missed something...):
i have an array with objects, the object is AddressCard and one if the properties is name.
so i send to my function string and with for statement looking all the matches inside my object collection array who contain AddressCArd object (bookArray) and if there is match i want to add this object to an array asnd return this array:
-(NSMutableArray *) lookup:(NSString *) name
{
NSMutableArray arr = [NSMutableArray array];
for(AddressCard *card in bookArray}
{
if([card.name rangeOfString: name].location == NSNotfound)
{
[arr addObject: card];
}
}
return arr;
}
You can do as this:
-(NSMutableArray *) lookup:(NSString *) name {
NSMutableArray *arr = [NSMutableArray array];
for(AddressCard *card in bookArray) {
//if([card.name isEqualToString:name]) {
if([[card.name capitalizedString] rangeOfString:[name capitalizedString]].location != NSNotFound)
[arr addObject:card];
}
}
return arr;
}
Here is the string from NSMutableArray:
(
(
"Some String Value"
)
)
This code displays the string value that I want, but however, it displays with the brackets and quotes. How do I remove them?
Thank you in advance!!
In your case it is 2D Array:
Something like this:
NSArray *arr=[NSArray arrayWithObject:#"asdf"];
NSArray *arr2=[NSArray arrayWithObjects:arr, nil];
You need to go to 2nd level to retrive it as :
NSLog(#"=> %#",arr2[0][0]);
NSString *string=arr2[0][0];
-(void)repeatArray:(NSArray *)array1
{
static NSMutableString *InsideString; // Better to use global Varaible declared in ViewDidLoad/loadView
NSArray *array = array1; //Its your array
for (int i = 0; i< [array count]; i++) {
if ([[array objectAtIndex:i] isKindOfClass:[NSArray class]]) {
[self repeatArray:[array objectAtIndex:i]];
} else if ([[array objectAtIndex:i] isKindOfClass:[NSString class]]) {
[InsideString appendString:[NSString stringWithFormat:#"%# ", [array objectAtIndex:i]]];
}
}
}
I'm trying to re-arrange words into alphabetical order. For example, tomato would become amoott, or stack would become ackst.
I've found some methods to do this in C with char arrays, but I'm having issues getting that to work within the confines of the NSString object.
Is there an easier way to do it within the NSString object itself?
You could store each of the string's characters into an NSArray of NSNumber objects and then sort that. Seems a bit expensive, so I would perhaps just use qsort() instead.
Here it's provided as an Objective-C category (untested):
NSString+SortExtension.h:
#import <Foundation/Foundation.h>
#interface NSString (SortExtension)
- (NSString *)sorted;
#end
NSString+SortExtension.m:
#import "NSString+SortExtension.h"
#implementation NSString (SortExtension)
- (NSString *)sorted
{
// init
NSUInteger length = [self length];
unichar *chars = (unichar *)malloc(sizeof(unichar) * length);
// extract
[self getCharacters:chars range:NSMakeRange(0, length)];
// sort (for western alphabets only)
qsort_b(chars, length, sizeof(unichar), ^(const void *l, const void *r) {
unichar left = *(unichar *)l;
unichar right = *(unichar *)r;
return (int)(left - right);
});
// recreate
NSString *sorted = [NSString stringWithCharacters:chars length:length];
// clean-up
free(chars);
return sorted;
}
#end
I think separate the string to an array of string(each string in the array contains only one char from the original string). Then sort the array will be OK. This is not efficient but is enough when the string is not very long. I've tested the code.
NSString *str = #"stack";
NSMutableArray *charArray = [NSMutableArray arrayWithCapacity:str.length];
for (int i=0; i<str.length; ++i) {
NSString *charStr = [str substringWithRange:NSMakeRange(i, 1)];
[charArray addObject:charStr];
}
NSString *sortedStr = [[charArray sortedArrayUsingSelector:#selector(localizedCaseInsensitiveCompare:)] componentsJoinedByString:#""];
// --------- Function To Make an Array from String
NSArray *makeArrayFromString(NSString *my_string) {
NSMutableArray *array = [[NSMutableArray alloc] init];
for (int i = 0; i < my_string.length; i ++) {
[array addObject:[NSString stringWithFormat:#"%c", [my_string characterAtIndex:i]]];
}
return array;
}
// --------- Function To Sort Array
NSArray *sortArrayAlphabetically(NSArray *my_array) {
my_array= [my_array sortedArrayUsingSelector:#selector(localizedCaseInsensitiveCompare:)];
return my_array;
}
// --------- Function Combine Array To Single String
NSString *combineArrayIntoString(NSArray *my_array) {
NSString * combinedString = [[my_array valueForKey:#"description"] componentsJoinedByString:#""];
return combinedString;
}
// Now you can call the functions as in below where string_to_arrange is your string
NSArray *blowUpArray;
blowUpArray = makeArrayFromString(string_to_arrange);
blowUpArray = sortArrayAlphabetically(blowUpArray);
NSString *arrayToString= combineArrayIntoString(blowUpArray);
NSLog(#"arranged string = %#",arrayToString);
Just another example using NSMutableString and sortUsingComparator:
NSMutableString *mutableString = [[NSMutableString alloc] initWithString:#"tomat"];
[mutableString appendString:#"o"];
NSLog(#"Orignal string: %#", mutableString);
NSMutableArray *charArray = [NSMutableArray array];
for (int i = 0; i < mutableString.length; ++i) {
[charArray addObject:[NSNumber numberWithChar:[mutableString characterAtIndex:i]]];
}
[charArray sortUsingComparator:^NSComparisonResult(id _Nonnull obj1, id _Nonnull obj2) {
if ([obj1 charValue] < [obj2 charValue]) return NSOrderedAscending;
return NSOrderedDescending;
}];
[mutableString setString:#""];
for (int i = 0; i < charArray.count; ++i) {
[mutableString appendFormat:#"%c", [charArray[i] charValue]];
}
NSLog(#"Sorted string: %#", mutableString);
Output:
Orignal string: tomato
Sorted string: amoott
I have NSTableView with two columns, and i wanna fill them entries from SQLite database.
this method is make query for table
-(void)getPersons
{
NSString *file = [[NSBundle mainBundle] pathForResource:#"persons" ofType:#"db"];
sqlite3 *database = NULL;
if (sqlite3_open([file UTF8String], &database)==SQLITE_OK)
{
NSLog(#"i open database");
sqlite3_exec(database, "select name,age from persons", MyCallback, persons, NULL);
}
sqlite3_close(database);
}
the problem appers in MyCallback method:
static int MyCallback(void *context, int count, char **values, char **columns)
{
NSMutableArray *persons = (NSMutableArray *)context;
for (int i=0; i < count; i++) {
NSString *columnname = [NSString stringWithUTF8String:columns[i]];
const char *nameCString = values[i];
if ([columnname isEqualTo:#"name"]) {
[persons addObject:[NSString stringWithUTF8String:nameCString]];
}
else {
[ages addObject:[NSString stringWithUTF8String:nameCString]];
}
}
return SQLITE_OK;
}
how can i write "age" entries into NSMutableArray *ages, if i can assign *context just for one NSMutableArray? (in this code, this is NSMutableArray *person)
Surely i should create a separate method for get age entries?
thanks.
In many simple cases like the one in your question it is convinient use most natural representation of tables in objective-c: array of dictionaries. Table is indexed collection of records - so it is an array, and each record is collection of key-value pairs - so it is a dictionary. And you need not change you code when you change column names or even number of colums.
...
NSMutableArray *allRecords= (NSMutableArray *)context;
NSString *columnName;
NSString *columnValue;
NSMutableDictionary * record = [NSMutableDictionary dictionary];
for (int i=0; i < count; i++) {
columnName = [NSString stringWithUTF8String:columns[i]];
if (values[i]){
columnValue = [NSString stringWithUTF8String:values[i]];
}
else{
columnValue = #"";
}
[record setObject:columnValue forKey:columnName];
}
[allRecords addObject:record];
...