Question

我有一个将用户输入（通过readline()）转换为变量列表的函数。我绝对希望R处理2种情况：

用户提供的数字范围将占用列表中的一个插槽
用户提供了一系列数字，每个数字将在列表中占据一个单独的位置。

代码如下：

library(stringr)
translatingVar<-function(answer,varList){# 'answer' is the user's input and 'varList' is a name that will store user's input
  var1<-NULL
  bool<-0
  y<-0
  varA<-list()
  answer<-strsplit(answer,",",fixed = TRUE)# splitting a string of input into separate intended inputs 
  for(i in 1:length(answer[[1]])){# 'for' loop to process each input
    answer[[1]][i]<-str_remove_all(answer[[1]][i],"[ ]")# removing any empty spaces
    if(is.na(as.numeric(answer[[1]][i]))){#checking if input can be translated to numeric format straight away
      if(!length(grep("all",answer[[1]][i],fixed=TRUE))>0){#Tried to create a variable to separate 2 situations.
        bool<-1
      }
#Here are bunch of 'if' functions that process different scenarios
      if(!length(grep(":",answer[[1]][i],fixed=TRUE))>0){
        varA[[i+y]]<-answer[[1]][i]
      }else if(grep(":",answer[[1]][i],fixed=TRUE)&bool==1){
        varA[[i+y]]<-c(as.numeric(strsplit(answer[[1]][i],":",fixed=TRUE)[[1]][1]):as.numeric(strsplit(answer[[1]][i],":",fixed=TRUE)[[1]][2]))
      }else if(grep("all",answer[[1]][i],fixed=TRUE)){
        answer[[1]][i]<-str_remove_all(answer[[1]][i],"[all ]")
        var1<-as.list(c(as.numeric(strsplit(answer[[1]][i],":",fixed=TRUE)[[1]][1]):as.numeric(strsplit(answer[[1]][i],":",fixed=TRUE)[[1]][2])))
        varA<-append(varA,var1)
        y<-length(var1)
      }else{
        varA[[i+y]]<-answer[[1]][i]
      }

    }else{
      varA[[i+y]]<-as.numeric(answer[[1]][i])
    }

  }
  assign(varList,varA,envir = .GlobalEnv)
}
ss<-readline()
translatingVar(ss,"Variables")

当前，我收到以下错误：

Error in as.numeric(strsplit(answer[[1]][i], ":", fixed = TRUE)[[1]][1]):as.numeric(strsplit(answer[[1]][i],  : 
  NA/NaN argument

我认为这意味着answer[[1][i]为空，因此无法采取进一步的措施。我试图移动'if'函数，并使用额外的变量来帮助R更好地识别不同的场景，但效果不佳。

所需结果：

输入-“ 1,2,3：5，全部6：8,9”

输出-列表（1,2，c（3：5），6,7,8,9）

Answer 1

仔细观察，我注意到bool变量位于for循环之外，这意味着它不会在每次迭代时都被覆盖。

以下更正的代码：

translatingVar<-function(answer,varList){
  var1<-NULL
  y<-0
  varA<-list()
  answer<-strsplit(answer,",",fixed = TRUE)
  for(i in 1:length(answer[[1]])){
    answer[[1]][i]<-str_remove_all(answer[[1]][i],"[ ]")
    bool<-0
    if(is.na(as.numeric(answer[[1]][i]))){
      if(!length(grep("all",answer[[1]][i],fixed=TRUE))>0){
        bool<-1
      }
      if(!length(grep(":",answer[[1]][i],fixed=TRUE))>0){
        varA[[i+y]]<-answer[[1]][i]
      }else if(grep("all",answer[[1]][i],fixed=TRUE)&&bool==0){
        answer[[1]][i]<-str_remove_all(answer[[1]][i],"[all ]")
        var1<-as.list(c(as.numeric(strsplit(answer[[1]][i],":",fixed=TRUE)[[1]][1]):as.numeric(strsplit(answer[[1]][i],":",fixed=TRUE)[[1]][2])))
        varA<-append(varA,var1)
        y<-length(var1)
      }else if(grep(":",answer[[1]][i],fixed=TRUE)&&bool==1){
        varA[[i+y]]<-c(as.numeric(strsplit(answer[[1]][i],":",fixed=TRUE)[[1]][1]):as.numeric(strsplit(answer[[1]][i],":",fixed=TRUE)[[1]][2]))
      }else{
        varA[[i+y]]<-answer[[1]][i]
      }

    }else{
      varA[[i+y]]<-as.numeric(answer[[1]][i])
    }

  }
  if(!length(which(lapply(varA,is.null)==TRUE))>0){
    assign(varList,varA,envir = .GlobalEnv)
  }
  assign(varList,varA[-which(lapply(varA,is.null)==TRUE)],envir = .GlobalEnv)
}

根据用户输入生成变量列表

1 个答案: