row-of-character pattern [计] 字符行模式
The ? character means to match zero or one instance of the previous pattern element; the * character means to match zero or more of the previous element.
字符表示匹配前面模式元素的零个或一个实例，* 字符表示匹配前面元素的零个或多个实例。
This expression is then retained by the Pattern class before it is passed on to the Matcher class to check for matches in the context of a character sequence.
Pattern 先保存要使用的表达式，然后将其传递给 Matcher 类以便在字符序列的上下文中检查其匹配情况。
You can use an underscore (Scala's standard wild card character) as a placeholder to catch any type of exception (really, to match any case in a pattern matching expression).
你可以使用一个下划线(Scala的标准通配符)作为占位符来捕捉任意类型的异常(不骗你，它可以匹配模式匹配表达式的任何case)。
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