我有一个创建函数的构造函数。有一个名为＆＃39; features＆＃39;的变量。这是构造函数的局部变量，另一个名为＆＃39;的变量是＆＃39;这是构造函数创建的函数的本地。这些在下面的代码中区分为：
1）## --> 'features' assignment 1 (see question)
features <- paramIN
2）## --> 'features' assignment 2 (see question)
features[!paramIN] <- p
三个观察结果;
1）如果我在返回的函数内但features <- paramIN之前移动features[!paramIN] <- p，程序也可以。这是有道理的，因为paramIN是返回函数内的自由变量，features是返回函数的本地变量，features <- paramIN在它是子集并分配之前声明并初始化features
2）如果我使用features[!paramIN] <<- p并在返回的函数之外保留features的第一个声明，程序也可以工作，而且，当features的第一个实例更新时使用返回的函数。在这种情况下，就返回的函数而言，features和paramIN都是自由变量。看来返回函数内的features引用在返回函数之外声明的features。一切都很好。
这是我的具体问题：
3）但是如果我使用features[!paramIN] <- p，但完全删除features <- paramIN，程序将失败，因为它找不到features。似乎第一个声明（在返回函数之外）是将features建立为两元素向量所必需的。但是内心的＆＃39; features是一个与外部＆＃39;不同的变量。 features;它是返回函数的局部函数，那么它的存在和结构如何通过返回函数之外的features声明来确定？
## make.Function
## ============
## Constructor to make a function that accepts a vector of one or two elements
## Input argument:
##
## paramIN: 2-element vector to initialize and subset'features'
## There are two instances of 'features':
## One is local to make.Function(), and the second is local to the function defined inside make.Function()
##
## Acceptable values for paramIN:
## paramIn=c(<double>,FALSE): The constructed function accepts
## a scalar double and assigns it to 'features[1]'
## paramIn=c(FALSE,<double>): The constructed function accepts
## a scalar double and assigns it to 'features[2]'
## paramIn=c(FALSE,FALSE): The constructed function accepts
## a 2-element vector of doubles and assigns it to 'features' -OR -
## The constructed function accepts
## a scalar double and assigns it to both elements of 'features'
make.Function <- function(paramIN=c(FALSE,FALSE)) {
## 'paramIN', and 'features' are local variables in make.Function
## --> 'features' assignment 1 (see question)
features <- paramIN
## This function is returned by make.Function
function(p) {
## --> 'features' assignment 2 (see question)
features[!paramIN] <- p
x <- features[1]
y <- features[2]
## This is a simple function
x+2*y
}
}