关于 QList的问题在 Qt 中
我正在使用 Qt 4.5,并且正在使用 QList
它是字符串列表的列表。
现在我想替换一个 stringList 中的一个字符串,但输入起来似乎很不寻常。我找到了以下方法,想知道是否可以:
QList <QStringList> pDataList;
pDataList[listIndex].replace(QStringIndex, newString);
现在,我不担心语法,但我想知道 pDataList 的指针在内存中是否相邻,所以使用 []
是可以的。还有其他方法吗?
I'm using Qt 4.5 and im working with a QList<QStringList>
which is a list of string list.
Now I want to replace one string inside one stringList but with it seems unusual to type. I have found the following way of doing it and was wondering if it is ok:
QList <QStringList> pDataList;
pDataList[listIndex].replace(QStringIndex, newString);
Now, I'm not worried about the syntax, but I want to know if pDataList
's pointers is adjascent in memory so that it is okay to use []
. Is there another way to do it?
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pDataList
的元素在内存中相邻的问题与是否可以使用operator[]
的问题无关。一般来说,
QList<>
不保证其元素在内存中相邻,但它确实会重载operator[]
来为您提供您正在查找的元素。执行此类操作时,您唯一需要担心的是确保
(pDataList.size() < listIndex)
。否则,您将索引不在列表中的元素,从而在调试中触发异常或在发布中触发未定义的行为。The issue of
pDataList
's elements being adjacent in memory is not related to the question of whether it is ok to useoperator[]
.In general,
QList<>
does not guarantee that its elements are adjacent in memory, but it does overloadoperator[]
to give you the element you're looking for nonetheless.The only thing you need to worry about when doing something like this is to make sure that
(pDataList.size() < listIndex)
. otherwise, you'll be indexing elements not in the list, triggering an exception in debug or undefined behavior in release.