将csv值转换为R中的表

Question

我有一些来自民意调查的数据，如下所示：

                                    Freetime_activities
1                       Travelling, On the PC, Clubbing
2                           Sports, On the PC, Clubbing
3                                              Clubbing
4                                             On the PC
5                       Travelling, On the PC, Clubbing
6                                             On the PC
7                               Watching TV, Travelling

我想获取每个值的计数（旅行多少次/在 PC 上等），但我无法拆分这些值。 R中是否有一个函数可以做例如：

split("A,B,C") -> 
1 A
2 B
3 C

或者是否有直接从列中计算值的直接解决方案？

Answer 1

我们可以使用strsplit通过分隔符", ")分割列，unlist输出list然后使用table得到频率

 tbl <- table(unlist(strsplit(as.character(df1$Freetime_activities),
                                          ", ")))
 as.data.frame(tbl)
 #         Var1 Freq
 #1    Clubbing    4
 #2   On the PC    5
 #3      Sports    1
 #4  Travelling    3
 #5 Watching TV    1

       

注意：这里使用as.character，以防列是factor，因为strsplit 只能采用character 向量。

或者另一种选择是使用scan 提取元素，然后使用table 获取频率。

 table(trimws(scan(text = as.character(df1$Freetime_activities),
                   what = "", sep = ",")))

或将read.table 与unlist 和table 一起使用

table(unlist(read.table(text = as.character(df1$Freetime_activities), 
           sep = ",", fill = TRUE, strip.white = TRUE)))

编辑：基于@David Arenburg 的 cmets。

数据

df1 <- structure(list(Freetime_activities = c("Travelling, On the PC, 
  Clubbing", 
"Sports, On the PC, Clubbing", "Clubbing", "On the PC", "Travelling, 
 On the PC, Clubbing", 
"On the PC", "Watching TV, Travelling")), 
 .Names = "Freetime_activities", 
 class = "data.frame", row.names = c("1", 
"2", "3", "4", "5", "6", "7"))