Eval("Substitute(""|@|"",""|"","""+Substitute("A|B|C","|",""")+""|""+Substitute(""|@|"",""|"",""")+""")")

中出现三次“+”，中间那个与前后两个的关系是怎样的？还是有点糊涂。请帮助讲解下这里的“头”、中、“尾”的分配。只有把这个公式彻底弄懂了，Eval（）的用法才能基本掌握吧。

Substitute("|@|","|","A")+"|"+Substitute("|@|","|","B")+"|"+Substitute("|@|","|","C")----------

==========================================================

你把这个公式写成“一翻一”Eval形式的公式你就知道“一翻二”这个是怎么来的了。也就知道其中为什么出现3个“+”了。

Substitute("|@|","|","A")+"|"+Substitute("|@|","|","B")+"|"+Substitute("|@|","|","C")----
================================================================================================================
头：Substitute("|@|","|","---------引号加倍：Substitute(""|@|"",""|"",""

尾：")-----------------------------引号加倍："")

产生中：Substitute("A|B|C","|","替换")

替换|：")+"|"+Substitute("|@|","|","-------------引号加倍："")+""|""+Substitute(""|@|"",""|"",""

得到中：Substitute("A|B|C","|",""")+""|""+Substitute(""|@|"",""|"",""")

组装：

Eval("头"+中+"尾")

得到：

Eval("Substitute(""|@|"",""|"","""+Substitute("A|B|C","|",""")+""|""+Substitute(""|@|"",""|"",""")+""")")

最终这些都是作为工具应用了，例如：

一翻二("A|B|C"→"A@A|B@B|C@C")
公式：Eval("Substitute(""|@|"",""|"","""+Substitute("A|B|C","|",""")+""|""+Substitute(""|@|"",""|"",""")+""")")
结果：A@A|B@B|C@C
 
一翻三("A|B|C"→"A@A#A|B@B#B|C@C#C")
公式：Eval("Substitute(""|@|#|"",""|"","""+Substitute("A|B|C","|",""")+""|""+Substitute(""|@|#|"",""|"",""")+""")")
结果：A@A#A|B@B#B|C@C#C
 
一翻四("A|B|C"→"A@A#A&A|B@B#B&B|C@C#C&C")
公式：Eval("Substitute(""|@|#|&|"",""|"","""+Substitute("A|B|C","|",""")+""|""+Substitute(""|@|#|&|"",""|"",""")+""")")
结果：A@A#A&A|B@B#B&B|C@C#C&C
------------
一翻六--------
公式：Eval("Substitute(""|@|#|$|%|&|"",""|"","""+Substitute("A|B|C|D","|",""")+""|""+Substitute(""|@|#|$|%|&|"",""|"",""")+""")")

以下是引用iyplx2425在2013-8-1 16:08:00的发言：
依样画瓢毕竟算不得本事。

没有一点“悟性”要掌握Eval函数，还有很长的路！