例如，在美国邮政编码是一个五位数，后面还可能跟有一个破折号加一个四位数。

For example, a postal code in the United States is a five-digit number, optionally followed by a dash and a four-digit number. Listing 1 shows the regular expression that describes that format.

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例如，在美国邮政编码是一个五位数，后面还可能跟有一个破折号加一个四位数。

For example, a postal code in the United States is a five-digit number, optionally followed by a dash and a four-digit number. Listing 1 shows the regular expression that describes that format.

youdao