如何从nsmutablearray中删除最多一个对象？

I want to insert a bunch of objects into a NSMutableArray. Then I would remove them one by one when the time fits. Every inserted objects must be removed.

我想将一堆对象插入到NSMutableArray中。然后我会在适合的时候逐个删除它们。必须删除每个插入的对象。

However, if I have several copies of the same object, I just want to remove one of them.

但是,如果我有同一个对象的多个副本,我只想删除其中一个。

How would I do that?

我该怎么办?

5 个解决方案

#1

NSMutableArray *arr = [@[@1, @1, @5, @6, @5] mutableCopy]; // a copy of your array
NSMutableSet *removedObjects = [NSMutableSet setWithArray:arr];
for (id obj in removedObjects) {
    [arr removeObjectAtIndex:[arr indexOfObject:obj]]; // removes the first identical object
}

Also note that if your array is filled with custom objects, you need to implements hash and isEqual: so the comparisons can work.

另请注意,如果您的数组中填充了自定义对象,则需要实现hash和isEqual:因此比较可以正常工作。

#2

are any of these functions what you are looking for?

您正在寻找的这些功能中的任何一个?

[array removeObjectAtIndex:(NSUInteger)];
[array removeLastObject];
[array removeObject:(id)];

#3

[myMutableArray removeObjectAtIndex: 0];

[myMutableArray removeLastObject];

To remove the first and last objects respectively.

分别删除第一个和最后一个对象。

#4

I don't think it's a good design for [NSMutableArray removeObject:] to remove all the occurences but we can avoid it by first getting an index using indexOfObject: and then removing the object using removeObjectAtIndex:

我不认为[NSMutableArray removeObject:]删除所有出现的好设计但我们可以通过首先使用indexOfObject获取索引来避免它:然后使用removeObjectAtIndex删除对象:

#5

i prefer using index of object; it will return the index of object first appeared in the array

我更喜欢使用对象索引;它将返回首先出现在数组中的对象索引

 NSMutableArray * first = [@[@"2",@"3",@"4",@"5"] mutableCopy];//your first array

    NSMutableArray * willBeAppend =  [@[@"2",@"3",@"4",@"5"] mutableCopy];//new objects to append

    [first addObjectsFromArray:willBeAppend];//append new objects

    id objectToBeRemoved = @"3";// object will be removed

    NSInteger objIx = [first indexOfObject:objectToBeRemoved];// index of object

    if (objIx != NSNotFound) {

        [first removeObjectAtIndex:objIx]; //remove object


        NSLog(@"%@",first);

    }

#1

NSMutableArray *arr = [@[@1, @1, @5, @6, @5] mutableCopy]; // a copy of your array
NSMutableSet *removedObjects = [NSMutableSet setWithArray:arr];
for (id obj in removedObjects) {
    [arr removeObjectAtIndex:[arr indexOfObject:obj]]; // removes the first identical object
}