That position number is needed in case the node has siblings of the same type and name, to indicate which one we're referring to.

位置号是必需的，以防节点有相同类型和名称的兄弟节点，这样可以表明我们引用的是哪个节点。

youdao

It can be arbitrarily set number of rows of welding knives and row position number of knives.

可任意设定焊接刀排数和刀排位置号。

youdao

There are more than 200 genes controlling and adjusting teeth development. They decide tooth position, number, size and shape, etc.

在牙齿的发育形成过程中有多达200多个基因参与调控，它们决定各个牙齿的位置、数目、大小和形状等。

youdao

The book entered The New York Times Best Sellers list at the number one position on September twenty-fifth.

VOA: special.2009.10.09

So this is like crossing off the person in position number 2 here.

这就像是划掉,2号位上的人或物。

哈佛公开课 - 计算机科学课程节选

And we certainly don't think that in fact most of us are in the position to actually crank out any kind of accurate number.

我们当然不会认为,多数人都能,得出更准确的数字。

耶鲁公开课 - 死亡课程节选

His harsh putdowns and bravado have put Cowell in position number 22 on our Celebrity 100 list.

FORBES: Idolatry

Among the new faces is Sale Sharks second row Chris Jones, who will make his debut for England playing out of position at number eight.

BBC: Vickery out to prove point

South Africa, who finished five points clear of England, scored the opening try after nine minutes through Burger, playing out of position at number eight on his return from a two-match ban.

BBC: South Africa 64-15 USA