Question

当我的while循环随机工作时，我很困惑？

how.many<-function(fruit, number){
  string<-paste("How many",fruit,"?",sep=" ")
  fruit_number<-readline(string)
  print("fruit number")
  print(fruit_number)
  print("number")
  print(number)
  while(fruit_number > number){
    print("inside while")
    print("fruit number")
    print(fruit_number)
    print("number")
    print(number)
    print("ERROR: too many for the budget")
    string<-paste("How many",fruit,"?",sep=" ")
    fruit_number<-readline(string)
  }
  return(as.numeric(fruit_number))
}

这是我调用此函数的时候：

> source("fruit.R")
> how.many("apple",6)
How many apple ?3
[1] "fruit number"
[1] "3"
[1] "number"
[1] 6
[1] 3
> how.many("apple",10)
How many apple ?9
[1] "fruit number"
[1] "9"
[1] "number"
[1] 10
[1] "inside while"
[1] "fruit number"
[1] "9"
[1] "number"
[1] 10
[1] "ERROR: too many for the budget"
How many apple ?7
[1] "inside while"
[1] "fruit number"
[1] "7"
[1] "number"
[1] 10
[1] "ERROR: too many for the budget"
How many apple ?2
[1] "inside while"
[1] "fruit number"
[1] "2"
[1] "number"
[1] 10
[1] "ERROR: too many for the budget"
How many apple ?1
[1] 1

任何提示？

Answer 1

将fruit_number转换为数字，而不是字符串。

e.g。

fruit_number <- as.numeric(readline(string))

或

fruit_number <- as.integer(readline(string))

否则将数字作为字符串进行比较，并且＆＃34; 9＆＃34;大于＆＃34; 10＆＃34;在字符串意义上。

为什么while循环随机工作？

1 个答案: