小萌在做開(kāi)發(fā)拖拽單元格移動(dòng)的時(shí)候遇到的坑，這是一個(gè)小萌忽略的問(wèn)題。removeObjectAtIndex和removeObject的兩者雖然都是刪除，可是卻有很大的不同

1、removeObject刪除對(duì)象

api上是這么解釋的。
Removes all occurrences in the array of a given object.
This method uses indexOfObject: to locate matches and then removes them by using removeObjectAtIndex:. Thus, matches are determined on the basis of an object’s response to the isEqual: message. If the array does not contain anObject, the method has no effect (although it does incur the overhead of searching the contents).

刪除NSMutableArray中所有isEqual:待刪對(duì)象的對(duì)象

也就是說(shuō)removeObject:可以刪除多個(gè)對(duì)象（只要符合isEqual:的都刪除掉，只要兩個(gè)對(duì)象相等都可以刪除掉）。

2、removeObjectAtIndex

api上這樣解釋的。

Removes the object at index .
To fill the gap, all elements beyond index are moved by subtracting 1 from their index.

Important:Important
Raises an exception NSRangeException if index is beyond the end of the array.

刪除指定NSMutableArray中指定index的對(duì)象，注意index不能越界，只能刪除一個(gè)元素。

3、舉例說(shuō)明

tempArray 臨時(shí)數(shù)組
[@"how", @"to", @"remove", @"remove", @"object",@"remove", @"true"]

就拿上面的數(shù)組舉例吧

（一）removeObject刪除

[tempArray removeObject:@"remove"];

輸出結(jié)果：

//所有@"remove"都被刪掉
[@"how", @"to", @"object", @"true"]

（二）removeObjectAtIndex刪除

[tempArray removeObjectAtIndex:2];

輸出結(jié)果：

只刪掉一個(gè)下標(biāo)為2的@"remove"元素，其他的都還在
[@"how", @"to", @"remove", @"object",@"remove", @"true"]