I am using a for loop to loop though and insert data into a NSMutableDictionary and then inserting that NSMutableDictionary into an NSMutableArray, the code is fairly simple and shown below:
for (NSDictionary *selectedOption in selectedOptions) {
NSString *name = selectedOption[#"name"];
NSString *value = selectedOption[#"value"];
[variantRow setObject:name forKey:#"name"];
[variantRow setObject:value forKey:#"value"];
[variantInfo addObject:variantRow];
}
The problem I am trying to solve is that *name and *value always gets the last value of the loop even for previously inserted dicts into the variantInfo NSMutableArray, I am assuming my problem is because I am inserting pointers etc, but I don't understand how else I can do it? I need to insert the values and have future inserts not affect previous ones.
I hope the description makes sense as its not to easy to explain.
You are modifying the same NSDictionary object reference(variantRow) in every iteration and appending it to the array variantInfo. You need to create a new NSDictionary object:
for (NSDictionary *selectedOption in selectedOptions) {
NSString *name = selectedOption[#"name"];
NSString *value = selectedOption[#"value"];
if(name && value) {
NSDictionary* newVariantRow = #{"name": name, #"value":value};
[variantInfo addObject: newVariantRow];
}
}
Related
I am using below function to check whether if an object in an array is present in another array. If the object not present, then I will ADD that object to the new array, or else that object will NOT be included in the new array that I instantiated.
+ (NSMutableArray *)loadUngroupedSpeakerList
{
NSUserDefaults *userDefaults = [NSUserDefaults standardUserDefaults];
NSMutableArray *speakerList = [[NSMutableArray alloc] init];
NSArray *speakerIDList = [userDefaults objectForKey:DATA_SPEAKER_IDLIST];
NSArray *speakerIDListGrouped = [userDefaults objectForKey:DATA_SPEAKER_IDLIST_GROUPED];
//**** this is for checking the contents of speakerIDListGrouped ****//
for(NSString *speakerID in speakerIDListGrouped)
{
NSLog(#"FLOWCHECK~ loadUngroupedSpeakerList check content:%#", speakerID);
}
for(NSString *speakerID in speakerIDList)
{
if(![speakerIDListGrouped containsObject:speakerID])
{
NSLog(#"FLOWCHECK~ loadUngroupedSpeakerList: speakerID: %#", speakerID);
NSDictionary *speakerDict = [userDefaults dictionaryForKey:[NSString stringWithFormat:#"%#%#", DATA_SPEAKER_DICT, speakerID]];
[speakerList addObject:speakerDict];
}
}
return speakerList;
}
In the above code, speakerList contains all the speakerIDs. While speakerIDListGrouped only contains the speakerIDs that are used in a group. My function needs to eliminate all the speakerIDs used in a group so I did it in a way just like the above code.
My Problem:
When I run the code, I notice that even if speakerIDListGrouped contains the object in speakerIDList, these two lines would still be executed
NSDictionary *speakerDict = [userDefaults dictionaryForKey:[NSString stringWithFormat:#"%#%#", DATA_SPEAKER_DICT, speakerID]];
[speakerList addObject:speakerDict];
Whereas to I understand, It should not happen. Because I only allowed them to be executed only if speakerIDList does not contain that object.
This is the log when I execute the code:
2015-06-15 19:31:24.849 soulbeats[1936:433953] FLOWCHECK~ loadUngroupedSpeakerList check content:72243140485836704
2015-06-15 19:31:24.850 soulbeats[1936:433953] FLOWCHECK~ loadUngroupedSpeakerList check content:7782687177520836128
2015-06-15 19:31:24.850 soulbeats[1936:433953] FLOWCHECK~ loadUngroupedSpeakerList: speakerID: 72243140485836704
2015-06-15 19:31:24.851 soulbeats[1936:433953] FLOWCHECK~ loadUngroupedSpeakerList: speakerID: 7782687177520836128
As can be seen, speakerIDListGrouped DOES contain the two objects. However, when I tried replacing the string inside the lower for loop by hardcoding it to one of the objects I printed on Log, which was 72243140485836704. The function now works properly, I mean it didn't execute the two lines I showed before.
I am now confused. What is the difference between the string I hardcoded and the one that was obtained from the array? The contents are the same.
Many Thanks!
I did the same thing it is working fine...
NSMutableArray *speakerList = [[NSMutableArray alloc] init];
NSArray *speakerIDList = #[#"a",#"b",#"c",#"d",#"e"];
NSArray *speakerIDListGrouped =#[#"a",#"b",#"f",#"g",#"h"];
for(NSString *speakerID in speakerIDListGrouped)
{
NSLog(#"%#", speakerID);
}
for(NSString *speakerID in speakerIDList)
{
if(![speakerIDListGrouped containsObject:speakerID])
{
NSLog(#"FLOWCHECK~ loadUngroupedSpeakerList: speakerID: %#", speakerID);
[speakerList addObject:speakerID];
}
}
There might be some issue with the objects inside the array....
This answer will help other's. It's very simple, use following method of NSArray
id commonObject = [array1 firstObjectCommonWithArray:array2];
Ref: https://developer.apple.com/documentation/foundation/nsarray/1408825-firstobjectcommonwitharray?language=objc
While trying to set a single key/value pair in NSMutableDictionary of NSMutableArray like:
[[self.items objectAtIndex:i] setValue:#"value" forKey:#"key"];
self.items is NSMutableArray and it have a list of NSMutableDictionaries
Instead of setting to that single object, it set it to all dictionaries in the list.
I have used this method before. But I don't know what is happening in this case.
I know NSArray have setValue:#"value" forKey:#"key method, but in this case I am using NSMutableArray
Here is a bit more block of code to help clarify my situation:
-(void)setItem:(id)sender
{
for (CellView *cell in self.CollectionView.visibleCells)
{
NSIndexPath *indexPath = [self.CollectionView indexPathForCell:cell];
int i = (indexPath.section * (mainItems.count)/3+ indexPath.row);
if (((UIButton *)sender).tag == i)
{
[[self.items objectAtIndex:i] setValue:#"value" forKey:#"key"];
}
}
}
Call setObject:forKey:, not setValue:forKey:. There is a difference.
Note that NSMutableArray extends NSArray so NSMutableArray has all of the methods of NSArray.
I also recommend you split your line up as well as use modern syntax:
NSMutableDictionary *dict = self.items[i];
dict[#"key"] = #"value";
NSMutableArray is a subclass of NSArray so all the NSArray methods are still there in NSMutatbleArray. You could try pulling it out and putting it back in to figure things out then reassemble your code after...
NSMutableDictionary *d = [self.items objectAtIndex:i];
[d setValue:#"value" forKey:#"key"];
[self.items setObject: d atIndexedSubscript: i];
This is a little more explicit which will allow you to debug it easier (not getting unexpected nils back, etc.).
Ok I got the issue.
I am working on a large pre-existing code. And I come to notice that The MutableDictionary was defined globally and the same object was being added to the MutableArray. So basically all the pointers in the MUtableArray where pointing to a single object.
I have a dictionary with key-value pair populated from JSON returned data.What I wish to do is use the dictionary to populate UITableView.
I have this structure for table:
[Product Name]
By [Manufacturer Name]
What this means is that key is Product Name and Value is Manufacturer Name. I need to get the name of the key and the name of the value. How can this be done? and is it possible without for-loop?
I'd use the enumerateKeysAndObjectsUsingBlock: method. The following code builds a list of the strings you require.
NSMutableArray *names = [NSMutableArray array];
[dictionary enumerateKeysAndObjectsUsingBlock: ^(NSString *key, NSString *object, BOOL *stop) {
[names addObject[NSString stringWithFormat:#"%# By %#",key, object]];
}];
You can use the keyEnumerator of NSDictionary and for each key look up the value. This could look something like this:
for (NSString *p in dict)
{
NSString *m = [dict objectForKey:p];
// do something with (p,m)
}
You should not be concerned with avoiding for-loops. After all, something like a for loop will always happen somewhere underneath.
If your keys are dynamic from json then you can use
NSArray *keys = [dictionary allkeys];
Then in the table View Cell for row at index path method you can populate the table view with the corresponding keys and their values.
NSArray * keys = [results allKeys];
for (int i = 0;i<[keys count];c++){
NSString* productName = [key objectAtIndex:i];
NSString* manufacturerName = [results objectForKey:productName];
}
Hope this helps...
I have assumed the name as strings, you can change the type according to your situation..
NSMutableDictionary *expense_ArrContents = [[NSMutableDictionary alloc]init];
for (int i = 1; i<=4; i++) {
NSMutableArray *current_row = [NSMutableArray arrayWithObjects:#"payer_id",#"Expense_Type_id",#"Category_Id",#"SubCategory_Id",nil];
[expense_ArrContents setObject:current_row forKey: [NSNumber numberWithInt:i]];
}
NSArray *newArray = [expense_ArrContents allKeysForObject:#"payer_id"];
NSLog(#"%#",[newArray description]);
i want to get the list of key values containing the particular object which is in the array of values stored in nsmutabledictionary for a particular key.
In the line where you get all the keys ([expense_ArrContents allKeysForObject:#"payer_id"];) you actually get keys for an object that is not in any of the array's items. This #"player_id" is different object than the #"player_id" you added in current_row. In fact, maybe all of your rows have different #"player_id" objects (except if the compiler has made some optimization - maybe it threats that same string literal as one object instead of creating new object for each iteration).
Try creating an NSString object for the #"player_id" which you add to the current_row and then get all the keys for that same object:
NSString* playerId = #"player_id";
for(){
NSMutableArray *current_row = [NSMutableArray arrayWithObjects: playerId,...];
...
}
NSArray *newArray = [expense_ArrContents allKeysForObject:playerId];
Your NSArray *newArray = [expense_ArrContents allKeysForObject:#"payer_id"]; will not return any value because in expense_ArrContents there is no such key(#"payer_id"), instead there are keys like 1,2,3 etc.What is your requirement?Want to see what all keys are there in expense_ArrContents just log
NSArray*keys=[expense_ArrContents allKeys];
Try this :
NSMutableArray *array_key=[[NSMutableArray alloc]init];
for (NSString *key in expense_ArrContents) {
if ([[expense_ArrContents objectForKey:key] containsObject:#"payer_id"]) {
[array_key addObject:key];
}
}
I am familiar with getting a string count from a known array
int numberOfWords = [self.wordArray count];
but I have an unknown number of strings in an unknown number of arrays, all referenced by a dictionary. This works - good.
NSMutableDictionary *eqClasses = [[NSMutableDictionary alloc] init];
The arrays and strings are added at runtime (with help of this board):
NSMutableArray* array = [eqClasses objectForKey:wordPattern];
if(!array) {
// create new array and add to dictionary if wordPattern not found
array = [NSMutableArray array];
[eqClasses setObject:array forKey:wordPattern];
}
[array addObject:tempWordStr];
Now I need to iterate through the dictionary and get the array with the largest word count. Is there a way to scroll through all the arrays in the dictionary without using a key (I won't know all the word patterns as they are generated dynamically), AND once I find the array with the most words, get that array/value and key/wordpattern?
Well, there is a way to get all the keys within a dictionary:
NSArray *keyArray = [myDict allKeys];
And then you just go through the array and get the object for each key.
A fast enumeration should work nicely.
for (NSString *string in NSArray){
...
} //Assuming your keys are strings!
You can save each string to a temporary string, and when encountering a new string, compare to find the longer one. If it's longer, replace the old string with the longer one.
Hope this helped! ^_^
^_^
Okay, so now that you have an array full of all the keys in the dictionary,
you can iterate through the entire array and get the corresponding value (the string) for each key.
NSArray *keyArray = [myDict allKeys]; //This gets all the keys
NSString *tempString = #""; //This is the string you will save the longest string in. It gets updated when a longer string is found in the following loop.
for (NSString *string in keyArray){
NSString *stringFromCurrentKey = [myDict objectForKey:string];
if(stringFromCurrentKey.length > tempString.length){
tempString = stringFromCurrentKey;
}
} //By the end, you should be left with the longest string contained in tempString!
^_^ Hope this made sense and helped!
Try this code:
NSArray *largestArray = nil;
for (NSString *key in dictionary)
{
NSArray *array = [dictionary objectForKey:key];
if (array.count > largestArray.count) // largestArray.count is 0 if largestArray is nil
{
largestArray = array;
}
}