For patterns with a leading minus sign (negative prefix), truncation occurs at the point of a nondigit character, including embedded minus signs.
对于带前置负号(负前缀)的模式,截断发生在非数字字符的点(包括了内嵌的负号)。
2
In other words, without the dollar sign to anchor the end of the string, a very long string with a matching prefix, such as "martin1234-cruft," would yield a false positive.