在 R 中的 while 循环中嵌套多个 if 语句

Question

是否可以在 while 循环中嵌套多个 if 语句？

我正在尝试创建一个简单的示例来向他们展示自己：

i <- 1 
while(i <=10) {
if(i > 6){
cat("i=",i,"and is bigger than 6.\n")
}else{if(3<i & i<6){
cat("i=",i,"and is between 3 and 6.\n")
}else{  
cat("i=",i,"and is 3 or less.\n")
}
i<-i+1
cat("At the bottom of the loop i is now =",i,"\n")
}

我的示例代码一直卡在 i=7 并希望永远运行。我怎样才能避免这种情况？

Answer 1

在第一个 else

之后，您还有一个额外的 {

i <- 1 
while(i <=10) {
  if(i > 6){
    cat("i=",i,"and is bigger than 6.\n")
  }else if(3<i & i<6){
    cat("i=",i,"and is between 3 and 6.\n")
  }else{  
    cat("i=",i,"and is 3 or less.\n")
  }
    i<-i+1
    cat("At the bottom of the loop i is now =",i,"\n")
}

Answer 2

如@Alex P 所述，您有一个额外的 {。

不过，您也可以通过检查 i 是否大于等于 3 来简化 else if（您已经知道 i 将小于或等于6 从它失败第一个 if 条件你检查 i > 6):

i <- 1 
while(i <=10) {
    if(i > 6) {
        cat("i =", i, "and is bigger than 6.\n")
    } else if(i >= 3) {
        cat("i =", i ,"and is between 3 and 6 inclusive.\n")
    } else {  
        cat("i =", i ,"and is less than 3.\n")
    }
    i = i + 1
    cat("At the bottom of the loop i is now =", i ,"\n")
}

输出：

i = 1 and is less than 3.
At the bottom of the loop i is now = 2 
i = 2 and is less than 3.
At the bottom of the loop i is now = 3 
i = 3 and is between 3 and 6 inclusive.
At the bottom of the loop i is now = 4 
i = 4 and is between 3 and 6 inclusive.
At the bottom of the loop i is now = 5 
i = 5 and is between 3 and 6 inclusive.
At the bottom of the loop i is now = 6 
i = 6 and is between 3 and 6 inclusive.
At the bottom of the loop i is now = 7 
i = 7 and is bigger than 6.
At the bottom of the loop i is now = 8 
i = 8 and is bigger than 6.
At the bottom of the loop i is now = 9 
i = 9 and is bigger than 6.
At the bottom of the loop i is now = 10 
i = 10 and is bigger than 6.
At the bottom of the loop i is now = 11

在 R 中的 while 循环中嵌套多个 if 语句

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