An iterator is a kind of code helper that lets you quickly access data in any collection or container, one at a time.
迭代器是某种代码助手，可以让您迅速地访问任何集合或容器中的数据，每次一个数据。
2
A query is a collection of counters, created in your custom code, to manage the collection of performance data.
查询是计数器的集合，它是用自定义代码创建的，用于管理性能数据的集合。
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The Rational PurifyPlus product has three components: Purify for memory error checking, Quantify for performance datacollection, and PureCoverage for code-coverage analysis.