R，如何在循环本身内增加 for 循环限制？

Question

我在 R 中工作，我试图在循环本身内更改 for 循环的限制，但我无法成功。

这是我的玩具和平代码：

setwd(".")
options(stringsAsFactors = FALSE)
cat("\014")
set.seed(11)


execution_limit <- 10

for(exe_i in 1:execution_limit)
{
    cat("(exe_i = ", exe_i," / ", execution_limit,  ")\n", sep="")
    Sys.sleep(0.1)

    if(exe_i == 7) {
            execution_limit <- 15
    }
}

打印输出：

(exe_i = 1 / 10)
(exe_i = 2 / 10)
(exe_i = 3 / 10)
(exe_i = 4 / 10)
(exe_i = 5 / 10)
(exe_i = 6 / 10)
(exe_i = 7 / 10)
(exe_i = 8 / 15)
(exe_i = 9 / 15)
(exe_i = 10 / 15)

循环在 10 次迭代后停止，但我想一直持续到第 15 次迭代。 我怎样才能做到这一点？

谢谢

Answer 1

你可以像这样使用while循环（注意你必须自己增加exe_i ）

execution_limit <- 10
exe_i <- 1
while(exe_i <= execution_limit)
{
    cat("(exe_i = ", exe_i," / ", execution_limit,  ")\n", sep="")
    Sys.sleep(0.1)

    if(exe_i == 7) {
            execution_limit <- 15
    }
    exe_i <- exe_i + 1
}

# (exe_i = 1 / 10)
# (exe_i = 2 / 10)
# (exe_i = 3 / 10)
# (exe_i = 4 / 10)
# (exe_i = 5 / 10)
# (exe_i = 6 / 10)
# (exe_i = 7 / 10)
# (exe_i = 8 / 15)
# (exe_i = 9 / 15)
# (exe_i = 10 / 15)
# (exe_i = 11 / 15)
# (exe_i = 12 / 15)
# (exe_i = 13 / 15)
# (exe_i = 14 / 15)
# (exe_i = 15 / 15)