如何从字符串中选择某些节点/单词

Question

我有这个密码

for $sea in distinct-values (doc("mondial.xml")//island/tokenize(@sea,"\s"))
let $count := count(doc("mondial.xml")//island[@sea = $sea]/tokenize(@sea,"\s"))
let $seacount := concat($sea," ",$count)
return $seacount

又回到了我身边

海洋-太古海洋3海-格林兰海0海-挪威海1海-巴伦茨海0

海-大西洋53海-拉布拉多海0.“等等。

如您所见，数字是$count，而sea部分是变量$sea。我现在要坚持的是选择$sea，它的最大值为$count的所有计数，并显示这个海名。我尝试过向以下内容添加一个$max变量：

 for $sea in distinct-values (doc("mondial.xml")//island/tokenize(@sea,"\s"))
let $count := count(doc("mondial.xml")//island[@sea = $sea]/tokenize(@sea,"\s"))
let $seacount := concat($sea," ",$count)
$max := concat($sea," ",max($count))
return $max

还尝试通过$count (降序)语句添加一个order，然后返回第一个节点：

for $sea in distinct-values (doc("mondial.xml")//island/tokenize(@sea,"\s"))
let $count := count(doc("mondial.xml")//island[@sea = $sea]/tokenize(@sea,"\s"))
let $seacount := concat($sea," ",$count)
order by $count descending
return $seacount[1]

我是走错路了还是？

Answer 1

这将返回结果序列的每个迭代的第一个节点。在这种情况下，$seacount总是一个1字符串的序列，所以您总是选择与('sea-value count')[1]等价的字符串，这就是单例字符串的值。若要只选择一个整体，请将整个查询包装为parens，以创建所有迭代的所有值的序列，然后选择其中的第一个：

(for $sea in distinct-values (doc("mondial.xml")//island/tokenize(@sea,"\s"))
let $count := count(doc("mondial.xml")//island[@sea = $sea]/tokenize(@sea,"\s"))
let $seacount := concat($sea," ",$count)
order by $count descending
return $seacount)[1]