Question

我刚开始在本科生的第二个学期学习R.很难在这里找到很多东西。我希望你能指出我正确的方向吗？

最初我不确定为什么要求线路出错，然后我认为他们正在尝试加载不在我的R安装中的软件包，所以我把它们打开了。我还想知道给我的数据是放在一个名为auto_mpg.txt的文件中。但是那条线之后的错误很难让我想象。

你能帮我理解一下吗？

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[Workspace loaded from ~/R/my_project/.RData]

> #################################################################
> #################  NIKITA TIWARI ############################
> #################################################################
> #################  DATA SUMMARY PJ1  ############################
> ##       mpg             cyl              wt           region     
> ##  Min.   : 9.00   Min.   :3.000   Min.   :1613   Min.   :1.000  
> ##  1st Qu.:17.50   1st Qu.:4.000   1st Qu.:2224   1st Qu.:1.000  
> ##  Median :23.00   Median :4.000   Median :2804   Median :1.000  
> ##  Mean   :23.51   Mean   :5.455   Mean   :2970   Mean   :1.573  
> ##  3rd Qu.:29.00   3rd Qu.:8.000   3rd Qu.:3608   3rd Qu.:2.000  
> ##  Max.   :46.60   Max.   :8.000   Max.   :5140   Max.   :3.000  
> ##                                                                
> ##             model    
> ##  ford pinto    :  6  
> ##  amc matador   :  5  
> ##  ford maverick :  5  
> ##  toyota corolla:  5  
> ##  amc gremlin   :  4  
> ##  amc hornet    :  4  
> ##  (Other)       :369
> #################################################################
> #################################################################
> 
> require(gridExtra) #given to me
Loading required package: gridExtra
Warning message:
package ‘gridExtra’ was built under R version 3.4.2 
> require(ggplot2) #given to me
Loading required package: ggplot2
Warning message:
package ‘ggplot2’ was built under R version 3.4.2 
> 
> 
> auto <- read.table("auto_mpg.txt", sep="\t", header = TRUE) #given to me
> head(auto)
            mpg.............cyl..............wt...........region
1 Min.   : 9.00   Min.   :3.000   Min.   :1613   Min.   :1.000  
2 1st Qu.:17.50   1st Qu.:4.000   1st Qu.:2224   1st Qu.:1.000  
3 Median :23.00   Median :4.000   Median :2804   Median :1.000  
4 Mean   :23.51   Mean   :5.455   Mean   :2970   Mean   :1.573  
5 3rd Qu.:29.00   3rd Qu.:8.000   3rd Qu.:3608   3rd Qu.:2.000  
6 Max.   :46.60   Max.   :8.000   Max.   :5140   Max.   :3.000  
> summary(auto) #given to me
                                     mpg.............cyl..............wt...........region
 1st Qu.:17.50   1st Qu.:4.000   1st Qu.:2224   1st Qu.:1.000  :1                        
 3rd Qu.:29.00   3rd Qu.:8.000   3rd Qu.:3608   3rd Qu.:2.000  :1                        
 Max.   :46.60   Max.   :8.000   Max.   :5140   Max.   :3.000  :1                        
 Mean   :23.51   Mean   :5.455   Mean   :2970   Mean   :1.573  :1                        
 Median :23.00   Median :4.000   Median :2804   Median :1.000  :1                        
 Min.   : 9.00   Min.   :3.000   Min.   :1613   Min.   :1.000  :1                        
> 
> 
> auto$cyl <- as.factor(auto$cyl)
Error in `$<-.data.frame`(`*tmp*`, cyl, value = integer(0)) : 
  replacement has 0 rows, data has 6
> auto$region <- as.factor(auto$region)
Error in `$<-.data.frame`(`*tmp*`, region, value = integer(0)) : 
  replacement has 0 rows, data has 6
> auto$cyl[auto$cyl == 1] <- "USA"
Error in `$<-.data.frame`(`*tmp*`, cyl, value = character(0)) : 
  replacement has 0 rows, data has 6
> auto$cyl[auto$cyl == 2] <- "EUR"
Error in `$<-.data.frame`(`*tmp*`, cyl, value = character(0)) : 
  replacement has 0 rows, data has 6
> auto$cyl[auto$cyl == 3] <- "ASIA"
Error in `$<-.data.frame`(`*tmp*`, cyl, value = character(0)) : 
  replacement has 0 rows, data has 6
> auto$region[auto$region == 1] <- "USA"
Error in `$<-.data.frame`(`*tmp*`, region, value = character(0)) : 
  replacement has 0 rows, data has 6
> auto$region[auto$region == 2] <- "EUR"
Error in `$<-.data.frame`(`*tmp*`, region, value = character(0)) : 
  replacement has 0 rows, data has 6
> auto$region[auto$region == 3] <- "ASIA"
Error in `$<-.data.frame`(`*tmp*`, region, value = character(0)) : 
  replacement has 0 rows, data has 6
> 
> auto$cyl <- factor(auto$cyl, levels=c("USA","EUR","ASIA"))
Error in `$<-.data.frame`(`*tmp*`, cyl, value = integer(0)) : 
  replacement has 0 rows, data has 6
> auto$region <- factor(auto$region, levels=c("USA","EUR","ASIA"))
Error in `$<-.data.frame`(`*tmp*`, region, value = integer(0)) : 
  replacement has 0 rows, data has 6
> summary(auto)
                                     mpg.............cyl..............wt...........region
 1st Qu.:17.50   1st Qu.:4.000   1st Qu.:2224   1st Qu.:1.000  :1                        
 3rd Qu.:29.00   3rd Qu.:8.000   3rd Qu.:3608   3rd Qu.:2.000  :1                        
 Max.   :46.60   Max.   :8.000   Max.   :5140   Max.   :3.000  :1                        
 Mean   :23.51   Mean   :5.455   Mean   :2970   Mean   :1.573  :1                        
 Median :23.00   Median :4.000   Median :2804   Median :1.000  :1                        
 Min.   : 9.00   Min.   :3.000   Min.   :1613   Min.   :1.000  :1                        
> 
> ###################################################################
> # calculate the mean mpg for cars, broken out by the number of 
> # cylinders in the car.
> ###################################################################
> 
> 
> ###################################################################
> #Provide a description of what you notice above
> ###################################################################
> # write a line describing the purpose of the next code chunk
> ###################################################################
> 
> 
> ###################################################################
> #provide a dsecriptiojn of what you notice above
> ###################################################################
> # Histograms
> ###################################################################
> # the next chunk of code is creating bar graphs and filling them 
> # with either region or cyl , with count on the y axis and 
> # mpg on the x axis
> ###################################################################
> ggplot(auto, aes(x = mpg, y = count, fill = cyl)) + geom_bar()
Don't know how to automatically pick scale for object of type tbl_df/tbl/data.frame. Defaulting to continuous.
Error in FUN(X[[i]], ...) : object 'count' not found
> ggplot(auto, aes(x = mpg, y = count, fill = region)) + geom_bar()
Don't know how to automatically pick scale for object of type tbl_df/tbl/data.frame. Defaulting to continuous.
Error in FUN(X[[i]], ...) : object 'count' not found
> ###################################################################
> # provide a description of what you notice above
> ###################################################################
> # write a line describe the purpose of the next chunck of code
> ###################################################################
> b1 <- ggplot(auto, aes(x=cyl, fill=cyl)) + geom_bar()
> b2 <- ggplot(auto, aes(x=region, fill=region)) + geom_bar()
> ###################################################################
> # the above code is used to creat a specific bar graph and it's 
> # x axis is the same a the fill so that it is more clear
> ###################################################################
> # the next chunck of code is used to fill the graph with the bars
> ###################################################################
> b3 <- ggplot(auto, aes(x = cyl, fill = region)) + geom_bar(position = "fill")
> b4 <- ggplot(auto, aes(x = region, fill = cyl)) + geom_bar(position = "fill")
> grid.arrange(b1, b2 ,b3, b4, ncol= 4)
Error in FUN(X[[i]], ...) : object 'cyl' not found
> ###################################################################
> # provide a description of what you notice above
> ###################################################################
> # the code below is going to make box plots of the data
> ###################################################################
> bp1 <- ggplot ( auto, aes(x = cyl, y = mpg, fill = cyl)) + geom_boxplot()
> bp2 <- ggplot ( auto, aes(x = region, y = mpg, fill = region)) + geom_boxplot()
> grid.arrange(bp1, bp2, ncol = 2)
Don't know how to automatically pick scale for object of type tbl_df/tbl/data.frame. Defaulting to continuous.
Error in FUN(X[[i]], ...) : object 'cyl' not found
> ###################################################################
> # provide a description of what you notice above
> ###################################################################
> # the code below is going to make box plots of the data spilt into
> # 3, 4, ,5, 6, 8 data with mpg being y axis, region being x axis
> # and region being the fill
> ###################################################################
> 
> 
> 
> 
> ###################################################################
> # provide a description of what you notice above
> ###################################################################
> # the code below is going to a jitter plot so basically its just a 
> # lot dots on a graph
> ###################################################################
> jp1 <- ggplot ( auto, aes(x = wt, y = mpg, fill = cyl)) + geom_jitter()
> jp2 <- ggplot ( auto, aes(x = wt, y = mpg, fill = region)) + geom_jitter()
> grid.arrange(jp1, jp2, ncol = 2)
Don't know how to automatically pick scale for object of type tbl_df/tbl/data.frame. Defaulting to continuous.
Error in FUN(X[[i]], ...) : object 'wt' not found
> ###################################################################
> # provide a description of what you notice above
> ###################################################################
> # the code below is going to a jitter plot but separate the graphs
> # into the different regions and only that region shows up on the
> # graph 
> ###################################################################
> fg1 <- ggplot ( auto, aes(x = wt, y = mpg, fill = cyl)) + geom_jitter()
> + facet_grid(region)
Error in facet_grid(region) : object 'region' not found
> fg1
Don't know how to automatically pick scale for object of type tbl_df/tbl/data.frame. Defaulting to continuous.
Error in FUN(X[[i]], ...) : object 'wt' not found
> 
> 
> ###################################################################
> # provide a description of what you notice above
> ###################################################################
> # the code below is going to a jitter plot but separate the graphs
> # into the different regions and into different cyl and only that 
> # cyl and that region show up in that graph
> ###################################################################
>

Answer 1

作为起点，错误消息 Error in $<-.data.frame(tmp, cyl, value = integer(0)) : replacement has 0 rows, data has 6 因为e而发生。 G。 auto$cyl会返回NULL。

这是因为执行时 auto <- read.table("auto_mpg.txt", sep="\t", header = TRUE) 根据您的代码，您的列名称不应该像它们那样命名。而不是e。 G。 cyl，auto对象中的相应列似乎是cyl..............。所以你要做的第一件事是交叉检查你的read.table函数是否按预期工作，列是按照它们的名字命名的。

此外，错误Don't know how to automatically pick scale for object of type tbl_df/tbl/data.frame. Defaulting to continuous. Error in FUN(X[[i]], ...) : object 'count' not found表示您的count对象中没有名为auto的列（执行summary(auto)时也未提及）。因此，我认为您必须自己计算列count的值。

最后，Don't know how to automatically pick scale for object of type tbl_df/tbl/data.frame. Defaulting to continuous. Error in FUN(X[[i]], ...) : object 'cyl' not found的目标是再次对列进行错误的命名。这也指向代码段末尾的以下错误消息。

Answer 2

欢迎使用Stack Overflow！使用R，您将学习一种重要的编程语言并开始使用有用的平台。也许您想要考虑阅读how you can create a minimal example和ask great questions。除了发布代码时，了解您希望使用代码实现的目标总是有益的 - 我建议在每个重要步骤中使用# comments。

正如@ rui-barradas怀疑我认为在阅读你的数据时存在问题（这是正常的情况:)虽然没有类似的数据示例很难说。您可以使用head(auto)并将结果添加到您的问题中，如果它不是任何方式的私人数据。

但是，您可能希望使用View(auto)来检查R是否正确读取数据集并生成所需的数据帧。（您可以class(auto)检查它是否确实是data.frame。）如果结果看起来很丑（例如列名显示很奇怪），请使用?read.table并探索如何自定义read.table()的选项（例如stringsAsFactors = FALSE或sep = ";"（即* .txt文件数据中使用的分隔符））以控制R将以何种方式读取数据。

R程序中的错误太多

2 个答案: