Excel的强大函数功能，为我们带来了极大方便，虽然它有200多个函数，但有时我们为实现一项规定的功能，可能用到几个函数或者采用嵌套函数，这样应用起来，也不太方便。其实对于我们经常用到的功能，我们可以创建自定义函数UDF(User—defined function)，它的运行与Excel中自带的函数完全相同。建立自定义函数有以下几个优点：建立自己特殊的功能和名称的函数；能将复杂的、嵌套的、多个原有的函数组合在一起，发挥更大的威力。 -Excel s powerful functions functions, brought us a great convenience, though it has more than 200 functions, but sometimes we have a requirement for the realization of functions, may use several functions or to use nested functions, so the application together, is not very convenient. In fact, we often used for functions, we can create a custom function UDF (User-defined function), its operation and Excel built-in function in exactly the same. The establishment of self-defined function has the following advantages: the establishment of its own special features and the name of the function　can be complex, nested, a number of original function together, and play a greater power.