根据确定性有限自动机每次到达最终状态时是否拆分字符串? [英] Split a string based on each time a Deterministic Finite Automata reaches a final state?

问题描述

我有一个问题，该问题的解决方案可以通过迭代解决，但是我想知道是否存在使用正则表达式和split()

I have a problem which has an solution that can be solved by iteration, but I'm wondering if there's a more elegant solution using regular expressions and split()

我有一个字符串(excel把它放在剪贴板上)，从本质上说，它是逗号分隔的.需要注意的是，当单元格值包含逗号时，整个单元格都用引号引起来(大概是为了避免该字符串中的逗号).字符串示例如下:

I have a string (which excel is putting on the clipboard), which is, in essence, comma delimited. The caveat is that when the cell values contain a comma, the whole cell is surrounded with quotation marks (presumably to escape the commas within that string). An example string is as follows:

123,12,"12,345",834,54,"1,111","98,273","1,923,002",23,"1,243"

现在，我想将该字符串优雅地拆分为单个单元格，但是要注意的是，我不能使用带有逗号作为分隔符的普通拆分表达式，因为它将对值中包含逗号的单元格进行划分.解决此问题的另一种方法是，如果逗号前面有 Even 个引号，我可以仅分割逗号.

Now, I want to elegantly split this string into individual cells, but the catch is I cannot use a normal split expression with comma as a delimiter, because it will divide cells that contain a comma in their value. Another way of looking at this problem, is that I can ONLY split on a comma if there is an EVEN number of quotation marks preceding the comma.

这很容易通过循环来解决，但是我想知道是否存在一个能够捕获此逻辑的正则expression.split函数.为了解决这个问题，我为逻辑构造了确定性有限自动机(DFA).

This is easy to solve with a loop, but I'm wondering if there's a regular expression.split function capable of capturing this logic. In an attempt to solve this problem, I constructed the Deterministic Finite Automata (DFA) for the logic.

现在的问题简化为:是否有办法拆分此字符串，以便每次在DFA中达到最终状态(此处为状态4)时都生成一个新的数组元素(对应于/s)?

The question now is reduced to the following: is there a way to split this string such that a new array element (corresponding to /s) is produced each time the final state (state 4 here) is reached in a DFA?

推荐答案

使用正则表达式(未转义):(?:(?:"[^"]*")|(?:[^,]*))

Using regex (unescaped): (?:(?:"[^"]*")|(?:[^,]*))

使用它并调用Regex.Matches()，它是.NET或在其他平台中的类似版本.

Use that and call Regex.Matches() which is .NET, or its analog in other platforms.

您可以将以上内容进一步扩展为:^(?:(?:"(?<Value>[^"]*)")|(?<Value>[^,]*))(?:,(?:(?:"(?<Value>[^"]*)")|(?<Value>[^,]*)))*$

You could further expand the above to this: ^(?:(?:"(?<Value>[^"]*)")|(?<Value>[^,]*))(?:,(?:(?:"(?<Value>[^"]*)")|(?<Value>[^,]*)))*$

这将以一枪的方式解析整个字符串，但是您需要命名组和每个组的多捕获功能才能工作(.NET支持).

This will parse the whole string in 1 shot, but you need named groups and multi-capture per group for this to work (.NET supports it).

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