本文给出一种将中缀表达式转换成前缀表达式的有效算法。
In this paper, a rapid algorithm from infix expression to prefix one is proposed.
中缀表示法是书写表达式的常见方式，而前缀和后缀表示法主要用于计算机科学领域。
Infix notation is a common way of writing expressions, while prefix and postfix notations are primarily used in computer science.
算术表达式中最常见的表示法形式有中缀、前缀和后缀表示法。
The three most common forms of notation in arithmetic expressions are infix, prefix, and postfix notations.
前缀用于在XML文档中导航时使用的任何路径表达式中。
The prefixes are then used in any paths expressions used to navigate in the XML document.
可选地，后面还可以跟着一个前缀为反斜杠的XPath表达式，以仅访问该消息部分的特定元素。
Optionally, there can follow an XPath expression prefixed by a backslash, to access only a specific element of the message part.
可选地，后面还可以跟着一个前缀为反斜杠的XPath表达式，以仅访问该消息部分的特定元素。
Optionally, there can follow an XPath expression prefixed by a backslash to access only a specific element of the message part.
XPath表达式不一定要使用相同的前缀，只需要名称空间uri相同即可。
The XPath expression does not need to use the same prefixes, only the same namespace URIs.
之后，再用名称空间前缀（result2）编写此表达式。
In the second part, write the expression with namespace prefixes (result2).
首先，尝试不用任何名称空间前缀(result1)编写此表达式。
First, try to write the expression without any namespace prefixes (result1).
用来定义要搜索的XML部分的XPath表达式没有包含名称空间前缀——换句话说，没有包含完全限定的元素名称(QName)。
The XPath expression used to define the XML part to search in does not contain the namespace prefix — the fully qualified element name (QName), in other words.
尽管向XPath表达式添加名称空间前缀需要进行一点额外的录入，但是该解决方案可行，且不增加额外的处理。
Although a little extra typing is required to add the namespace prefixes to the XPath expressions, this solution works and doesn't add extra processing.
同样，必须非常小心地处理XPath表达式中的前缀。
Again, you have to be very careful about prefixes in XPath expressions.
选项2：向XPath表达式添加名称空间前缀。
最重要的一点是XPath表达式只能引用名称空间前缀限定的元素和属性名。
Foremost among them is that XPath expressions can only reference namespace-qualified element and attribute names by the use of namespace prefixes.
向XPath表达式添加名称空间前缀。
事实上，如果XML文档使用默认名称空间，那么尽管目标文档没有使用前缀，XPath表达式也必须使用前缀。
Indeed, when the XML document USES the default namespace, the XPath expression must use a prefix even though the target document does not.
如果有任何一个步骤忘记使用这个前缀，那么表达式不会返回任何内容，并且很难搞清楚究竟是哪一步出的错。
If you forget to mention a prefix in any step, your expression will return nothing-an error for which it's difficult to track the cause.
主题表达式包含表达式类型、完全限定主题名称和前缀映射。
A topic expression is defined in terms of expression type, fully qualified topic name, and prefix mapping.
还需注意，在XPath表达式中，必须使用相应的名称空间前缀作为所有元素的前缀。
Also note that in XPath expressions, you must prefix all elements with the appropriate namespace prefix.
如果使用正则表达式，你必须使用~*前缀选择不区分大小写的匹配或者~ 选择区分大小写的匹配。
To use regular expressions, you must use the prefix ~* for case insensitive match and ~ for case sensitive match.
后缀和前缀增量运算符表达式中的评价如何？
How is the postfix and prefix increment operator evaluated in an expression?
获取表达式前缀，该前缀标识受表达式编辑器实现支持的表达式字符串。
Gets the expression prefix that identifies expression strings that are supported by the expression editor implementation.
获取表达式前缀，该前缀标识受表达式编辑器实现支持的表达式字符串。
Gets the expression prefix that identifies expression strings that are supported by the expression editor implementation.
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