nsmutablearray

平时使用 NSMutableArray 中经常用到遍历删除数组元素的问题。 一般第一个想法是使用一下 forin 就解决了，但是老司机都会知道使用 forin 做删除操作的时候会 crash。 报错的原因是： 当数组在枚举的时候被修改了，因为数组规定在 forin 遍历的时候不能修改数组元素。 但是有一种特殊情况，就是在删除数组最后一个元素的时候可以使用 forin ,因为到最后一个元素的时候 forin 枚举已经结束了，这时候删除元素不会影响到 forin 工作。 NSMutableArray *nameArray = @[@"1", @"2", @"3", @"4"]; 使用倒序 forin 删除元素 //创建逆序遍历 NSEnumerator *enume = [nameArray reverseObjectEnumerator]; for (NSString *name in enumerator) { if ([name isEqualToString:@"2"]) { [array removeObject:name]; } } 使用 for 循环进行遍历删除 遍历整个数组，找到对应的元素，然后执行删除操作 for (int i = 0; i < count; ++i) { NSString *name = nameArray[i]; if ([name

What is the difference b/w NSArray and NSMutableArray ? NSMutableArray (and all other classes with Mutable in the name) can be modified. So, if you create a plain NSArray , you cannot change its contents later (without recreating it). But if you create an NSMutableArray , you can change it — you'll notice it has methods like -addObject: and -insertObject:atIndex: . See the documentation for details. The "mutable" types are classes which can be changed after they've been initialized, like NSMutableString vs NSString . Jagat Dave NSArray : in NSArray we can not change index.... Means fix array.

As above. Would be helpful to know. Thanks! Here are two options: - (NSMutableArray *)createMutableArray1:(NSArray *)array { return [NSMutableArray arrayWithArray:array]; } - (NSMutableArray *)createMutableArray2:(NSArray *)array { return [[array mutableCopy] autorelease]; } Use -mutableCopy and make sure to balance the retain count. NSMutableArray *mutableArray = [[immutableArray mutableCopy] autorelease]; dhaya Try this one NSMutableArray *array = [[NSMutableArray alloc]initWithArray:your_array_name]; 来源： https://stackoverflow.com/questions/3222122/converting-nsarray-to-nsmutablearray

I made a mistake while creating a TableView class , and accidentally kept my @property as copy when I defined it: @property (copy, nonatomic) NSMutableArray *words; I initialised the array "correctly": (note this is the third attempt, so please ignore the fact that I'm not using mutableCopy and other better ways of doing this) NSArray *fixedWords = @[@"Eeny", @"Meeny", @"Miny", @"Moe", @"Catch", @"A", @"Tiger", @"By", @"His", @"Toe"]; NSMutableArray *mutWords = [[NSMutableArray alloc] initWithArray:fixedWords]; self.words = mutWords; However when I later came to reorder the array, it crashed

So I have a nsmutablearray with a bunch of objects in it. I want to create a comma separated string of the id value of each object. rdelmar Use the NSArray instance method componentsJoinedByString: . In Objective-C: - (NSString *)componentsJoinedByString:(NSString *)separator In Swift: func componentsJoinedByString(separator: String) -> String Example: In Objective-C: NSString *joinedComponents = [array componentsJoinedByString:@","]; In Swift: let joinedComponents = array.joined(seperator: ",") If you're searching for the same solution in Swift, you can use this: var array:Array<String> = [

Hi l am trying to create a fourates lists from an restaurants Object, my application has a list of different restaurants, l want the ability for users to add favourate restaurants, and this code is not working - (IBAction)toggleFav:(id)sender { Restaurant *resto = [self restaure]; NSMutableDictionary *dic = [[NSMutableDictionary alloc] init]; [dic setObject:resto.price forKey:@"restoPrice"]; [dic setObject:resto.restaurantId forKey:@"restaurantId"]; [dic setObject:resto.restoAbout forKey:@"restoAbout"]; [dic setObject:resto.restoAddress forKey:@"restoAddress"]; [dic setObject:resto