I have a NSArray containing a list of NSDictionary. Like:
NSArray *array = ...;
NSDictionary *item = [array objectAtIndex:0];
NSLog (#"quantity: %#", [item objectForKey: #"quantity"]);
How can I sum all the quantities contained in all dictionaries of the array?
I think you can try KVC
NSMutableArray *goods = [[NSMutableArray alloc] init];
NSString *key = #"quantity";
[goods addObject:#{key:#(1)}];
[goods addObject:#{key:#(2)}];
[goods addObject:#{key:#(3)}];
NSNumber *sum = [goods valueForKeyPath:#"#sum.quantity"];
NSLog(#"sum = %#", sum);
If you call valueForKey: on an array it gives you an array of all the values for that key, so [array valueForKey:#"quantity"] will give you an array which you can loop over and sum all the values.
NSMutableArray *quantityArray = [item objectForKey: #"quantity"];
int total =0;
for(int i=0;i<[quantityArray count];i++)
{
total+= [quantityArray objectAtIndex:i];
}
Related
I have an NSString filled with objects seperated by a comma
NSString *string = #"1,2,3,4";
I need to seperate those numbers and store then into an array while editing them, the result should be
element 0 = 0:1,
element 1 = 1:2,
element 2 = 2:3,
element 3 = 3:4.
How can i add those to my objects in the string ??
Thanks.
P.S : EDIT
I already did that :
NSString *string = #"1,2,3,4";
NSArray *array = [string componentsSeparatedByString:#","];
[array objectAtIndex:0];//1
[array objectAtIndex:1];//2
[array objectAtIndex:2];//3
[array objectAtIndex:3];//4
I need the result to be :
[array objectAtIndex:0];//0:1
[array objectAtIndex:1];//1:2
[array objectAtIndex:2];//2:3
[array objectAtIndex:3];//3:4
In lieu of a built in map function (yey for Swift) you would have to iterate over the array and construct a new array containing the desired strings:
NSString *string = #"1,2,3,4";
NSArray *array = [string componentsSeparatedByString:#","];
NSMutableArray *newArray = [NSMutableArray arrayWithCapacity:array.count];
[array enumerateObjectsUsingBlock:^(id obj, NSUInteger idx, BOOL *stop) {
[newArray addObject:[NSString stringWithFormat:#"%lu:%#", (unsigned long)idx, obj]];
}];
The first thing you need to do is separate the string into an array of component parts - NSString has a handy method for that : '-componentsSeparatedByString'. Code should be something like this :
NSArray *components = [string componentsSeparatedByString:#","];
So that gives you 4 NSString objects in your array. You could then iterate through them to make compound objects in your array, though you arent exactly clear how or why you need those. Maybe something like this :
NSMutableArray *resultItems = [NSMutableArray array];
for (NSString *item in components)
{
NSString *newItem = [NSString stringWithFormat:#"%#: ... create your new item", item];
[resultItems addObject:newItem];
}
How about this?
NSString *string = #"1,2,3,4";
NSArray *myOldarray = [string componentsSeparatedByString:#","];
NSMutableArray *myNewArray = [[NSMutableArray alloc] init];
for (int i=0;i<myOldarray.count;i++) {
[myNewArray addObject:[NSString stringWithFormat:#"%#:%d", [myOldarray objectAtIndex:i], ([[myOldarray objectAtIndex:i] intValue]+1)]];
}
// now you have myNewArray what you want.
This is with consideration that in array you want number:number+1
I have a twodimensional array where i i would like to print all second values of the objects into an UIlabel homePlayersFouls. the problem is i do not know how to this.
I have tried following things:
componentsJoinedByString:#"\n".
This will just print (
The other thing ive tried is this:
[[homePlayersArray objectAtIndex:i] objectAtIndex:1];
this just prints 0 since it looping and deleting the content inside label
i've checked wether there is something wrong the the array, but when i do this inside the loop:
nslog(#"%#",[[homePlayersArray objectAtIndex:i] objectAtIndex:1];);
It prints all 0 0 0 which is the 3 second values in my objects.
The question is then how can i print all my second values in all the objects in the array into an UIlabel?
here is the complete code:
for (int i=0;i<[homeNumbersArray count];i++){
NSArray *tempArray = [[NSArray alloc] initWithObjects:[homeNumbersArray objectAtIndex:i],[NSNumber numberWithInt:0], nil];
[homePlayersArray addObject:tempArray];
NSObject* someObject = [[homePlayersArray objectAtIndex:i] objectAtIndex:1];
homePlayersFouls.text = [NSString stringWithFormat:#"%#", someObject];
}
You need:
homePlayersFouls.text = [homePlayersFouls.text stringByAppendingString:[NSString stringWithFormat:#"%#", someObject]];
NSMutableString *fouls = [NSMutableString string];
for (int i=0;i<[homeNumbersArray count];i++){
NSArray *tempArray = [[NSArray alloc] initWithObjects:[homeNumbersArray objectAtIndex:i],[NSNumber numberWithInt:0], nil];
[homePlayersArray addObject:tempArray];
NSObject* someObject = [[homePlayersArray objectAtIndex:i] objectAtIndex:1];
[fouls appendFormat:#"%#", someObject];
}
homePlayersFouls.text = fouls;
OK so I know that dictionaries can't be sorted. But, say I have NSMutableArray *keys = [someDictionary allKeys]; Now, I want to sort those keys, based on the corresponding values in the dictionary (alphabetically). So if the dictionary contains key=someString, then I want to sort keys based on the strings they correspond to. I think its some application of sortUsingComparator but its a little out of my reach at this point.
NSArray *keys = [someDictionary allKeys];
NSArray *sortedKeys = [keys sortedArrayUsingComparator:^NSComparisonResult(id a, id b) {
NSString *first = [someDictionary objectForKey:a];
NSString *second = [someDictionary objectForKey:b];
return [first compare:second];
}];
NSDictionary *dict = // however you obtain the dictionary
NSMutableArray *sortedKeys = [NSMutableArray array];
NSArray *objs = [dict allValues];
NSArray *sortedObjs = [objs sortedArrayUsingSelector:#selector(compare:)];
for (NSString *s in sortedObjs)
[sortedKeys addObjectsFromArray:[dict allKeysForObject:s]];
Now sortedKey will contain the keys sorted by their corresponding objects.
Sort keys of NSDictionary based on dictionary keys
Abobe is for returning a sorted array with based on dictionary content, this is for returning an array sorted by dictionary key:
NSArray *keys = [theDictionary allKeys];
NSArray *sortedKeys = [keys sortedArrayUsingComparator:^NSComparisonResult(id a, id b) {
return [a compare:b];
}];
NSMutableArray *sortedValues = [NSMutableArray new];
for(NSString *key in sortedKeys)
[sortedValues addObject:[dictFilterValues objectForKey:key]];
Just write it here cause I didn't find it anywhere: To get an alphanumeric sorted NSDictionary back from an NSDictionary based on the value - which in my case was neccessary - you can do the following:
//sort typeDict alphanumeric to show it in order of values
NSArray *keys = [typeDict allKeys];
NSArray *sortedKeys = [keys sortedArrayUsingComparator:^NSComparisonResult(id a, id b) {
NSString *first = [typeDict objectForKey:a];
NSString *second = [typeDict objectForKey:b];
return [first compare:second];
}];
NSLog(#"sorted Array: %#", sortedKeys);
NSMutableDictionary *sortedTypeDict = [NSMutableDictionary dictionary];
int counter = 0;
for(int i=0; i < [typeDict count]; i++){
NSString *val = [typeDict objectForKey:[sortedKeys objectAtIndex:counter]];
NSString *thekey = [sortedKeys objectAtIndex:counter];
[sortedTypeDict setObject:val forKey:thekey];
counter++;
}
NSLog(#"\n\nsorted dict: %#", sortedTypeDict);
Not a big deal!
If any value from the dictionary is null then use this code
NSArray *keys = [typeDict allKeys];
NSSortDescriptor *sd = [[NSSortDescriptor alloc] initWithKey:nil ascending:YES];
NSArray *sortedKeys = [keys sortedArrayUsingDescriptors:#[sd]];
NSLog(#"SORT 1 %#",sortedKeys);
NSMutableDictionary *sortedTypeDict = [NSMutableDictionary dictionary];
int counter = 0;
for(int i=0; i < [typeDict count]; i++){
id val = [typeDict objectForKey:[sortedKeys objectAtIndex:counter]];
NSString *thekey = [sortedKeys objectAtIndex:counter];
[sortedTypeDict setObject:val forKey:thekey];
counter++;
}
NSLog(#"\n\nsorted dict: %#", sortedTypeDict);
I'm new to Objective-C and I'm trying to create a simple dictionary style app for personal use. Right now I'm attempting to make a loop that prints randomly selected NSArrays that have been added to an NSDictionary. I'd like to print each array only once. Here is the code I'm working with:
NSArray *catList = [NSArray arrayWithObjects:#"Lion", #"Snow Leopard", #"Cheetah", nil];
NSArray *dogList = [NSArray arrayWithObjects:#"Dachshund", #"Pitt Bull", #"Pug", nil];
...
NSMutableDictionary *wordDictionary = [[NSMutableDictionary alloc] init];
[wordDictionary setObject: catList forKey:#"Cats"];
[wordDictionary setObject: dogList forKey:#"Dogs"];
...
NSInteger keyCount = [[wordDictionary allKeys] count];
NSInteger randomKeyIndex = arc4random() % keyCount;
int i = keyCount;
for (i=i; i>0; i--) {
NSString *randomKey = [[wordDictionary allKeys] objectAtIndex:randomKeyIndex];
NSMutableArray *randomlySelectedArray = [wordDictionary objectForKey:randomKey];
NSLog(#"%#", randomlySelectedArray);
}
This code prints the same array "i" times. Any pointers on how to exclude previously printed arrays from being printed again?
I'm wondering if removeObjectForKey: could be of any use.
You just need to re-calculate the random key index every time you go through the loop, and then, as you suggest, use removeObjectForKey:.
Something like this:
NSArray *catList = [NSArray arrayWithObjects:#"Lion", #"Snow Leopard", #"Cheetah", nil];
NSArray *dogList = [NSArray arrayWithObjects:#"Dachshund", #"Pitt Bull", #"Pug", nil];
//...
NSMutableDictionary *wordDictionary = [[NSMutableDictionary alloc] init];
[wordDictionary setObject: catList forKey:#"Cats"];
[wordDictionary setObject: dogList forKey:#"Dogs"];
//...
while ([wordDictionary count] > 0) {
NSInteger keyCount = [wordDictionary count];
NSInteger randomKeyIndex = arc4random() % keyCount;
NSString *randomKey = [[wordDictionary allKeys] objectAtIndex:randomKeyIndex];
NSMutableArray *randomlySelectedArray = [wordDictionary objectForKey:randomKey];
NSLog(#"%#", randomlySelectedArray);
[wordDictionary removeObjectForKey: randomKey];
}
In your code, you generate a random randomKeyIndex, then use it without changing its value i times in the loop. So you get i times the same array.
NSInteger randomKeyIndex = arc4random() % keyCount;
// ...
for (i=i; i>0; i--) {
NSString *randomKey = [[wordDictionary allKeys] objectAtIndex:randomKeyIndex];
// ...
}
As you say removeObjectForKey is an option for you, you can change your code into something like this:
NSInteger keyCount = [[wordDictionary allKeys] count];
for (i=keyCount; i>0; i--) {
NSInteger randomKeyIndex = arc4random() % keyCount;
NSString *randomKey = [[wordDictionary allKeys] objectAtIndex:randomKeyIndex];
NSMutableArray *randomlySelectedArray = [wordDictionary objectForKey:randomKey];
[wordDictionary removeObjectForKey:randomKey];
keyCount--;
NSLog(#"%#", randomlySelectedArray);
}
I have an Array {-1,0,1,2,3,4...}
I am trying to find whether an element exist in these number or not, code is not working
NSInteger ind = [favArray indexOfObject:[NSNumber numberWithInt:3]];
in ind i am always getting 2147483647
I am filling my array like this
//Loading favArray from favs.plist
NSString* favPlistPath = [[NSBundle mainBundle] pathForResource:#"favs" ofType:#"plist"];
NSMutableDictionary* favPlistDict = [[NSMutableDictionary alloc] initWithContentsOfFile:favPlistPath];
NSString *favString = [favPlistDict objectForKey:#"list"];
NSArray *favList = [favString componentsSeparatedByString:#","];
//int n = [[favList objectAtIndex:0] intValue];
favArray = [[NSMutableArray alloc] initWithCapacity:100];
if([favList count]>1)
{
for(int i=1; i<[favList count]; i++)
{
NSNumber *f = [favList objectAtIndex:i];
[favArray insertObject:f atIndex:(i-1)];
}
}
That's the value of NSNotFound, which means that favArray contains no object that isEqual: to [NSNumber numberWithInt:3]. Check your array.
After second edit:
Your favList array is filled with NSString objects. You should convert the string objects to NSNumber objects before inserting them in favArray:
NSNumber *f = [NSNumber numberWithInt:[[favList objectAtIndex:i] intValue]];