当在R中的for循环中运行一个函数时,会跳出for循环 [英] breaking out of for loop when running a function inside a for loop in R
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问题描述
foo
。当我为循环运行时,我希望在<$ c>时跳过 foo
的其余部分$ c> foo
最初返回 0
的值。但是, break
在函数内部不起作用。 现在写入,我得到一个错误消息,没有循环打破,跳到顶层
。
有什么建议?
foo < - function(x) {
y< - x-2
if(y == 0){break}#如何告诉for循环跳过
z< - y + 100
z
$ b $(b在1:3中){
print(foo(i))
}
$ c不可否认的是,我的R知识是稀疏的,而且是干编码的,但是下面的代码应该可以工作:
$ b $ foo < - function(x){
y < - x-2
if(y == 0){return(NULL)}#return NULL然后检查它
z< -y + 100
z
}
for(i in 1: 3){
j < - foo(i)
if(is.null(j)){break}
print(j)
}
$编辑:更新后检查后代
Suppose you have the following function foo
. When I'm running a for
loop, I'd like it to skip the remainder of foo
when foo
initially returns the value of 0
. However, break
doesn't work when it's inside a function.
As it's currently written, I get an error message, no loop to break from, jumping to top level
.
Any suggestions?
foo <- function(x) {
y <- x-2
if (y==0) {break} # how do I tell the for loop to skip this
z <- y + 100
z
}
for (i in 1:3) {
print(foo(i))
}
解决方案 Admittedly my R knowledge is sparse and this is drycoded, but something like the following should work:
foo <- function(x) {
y <- x-2
if (y==0) {return(NULL)} # return NULL then check for it
z <- y + 100
z
}
for (i in 1:3) {
j <- foo(i)
if(is.null(j)) {break}
print(j)
}
Edit: updated null check for posterity
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