Rather than split the numeric sequence into individual digits and write complex code, a regex can test for validity.

regex不会把数字序列分隔为单个数字并编写复杂的代码，而是会测试其有效性。

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The test rule section of the RegEx editor, which is shown in Figure 6, is used to test your rule on a set of sample text snippets.

使用RegEx编辑器的Test Rule部分(见图6)在一组示例文本片段上测试规则。

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Such a little program is useful if you want to test or refine a regex.

如果需要测试或改进regex，则这种小型程序非常有用。

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