R動態創建數據表列

Question

我有一個名為tmp.df.lhs.denorm的數據表，它在前面提供了前兩行：

    > dput(tmp.df.lhs.denorm[1:2])
structure(list(rules = c("{} => {Dental anesthetic products-Injectables cartridges|2288210-Septocaine Cart 4% w/EPI}", 
"{Dental small equipment-Water distiller parts & acc|5528005-EzeeKleen 2.5HD UV Lamp1,Dental small equipment-Water distiller parts & acc|5528005-EzeeKleen 2.5HD UV Lamp2} => {Dental small equipment-Water distiller parts & acc|5528004-EzeeKleen 2.5HD RO Membra}"
), support = c(0.501710236989983, 0.000610798924993892), confidence = c(0.501710236989983, 
1), lift = c(1, 1637.2), rule.id = 1:2, lhs_1 = c(NA, "Dental small equipment-Water distiller parts & acc|5528005-EzeeKleen 2.5HD UV Lamp1"
), lhs_2 = c(NA, "Dental small equipment-Water distiller parts & acc|5528005-EzeeKleen 2.5HD UV Lamp2"
)), .Names = c("rules", "support", "confidence", "lift", "rule.id", 
"lhs_1", "lhs_2"), class = c("data.table", "data.frame"), row.names = c(NA, 
-2L), .internal.selfref = <pointer: 0x0000000007120788>)

注意列lhs_1和lhs_2是str在列規則上拆分的乘積。

我的問題是，對於不同的數據，列規則可能包含用逗號分隔的不同數量的規則，例如，我可能已經獲得3列lhs_1，lhs_2和lhs_3等，這取決於我在列規則中有多少個逗號。 解決方案是確定固定數量的lhs_ *列（我的代碼中的參數為6），其中此特定示例dt tmp.df.lhs.denorm將與其他4個空列合並，名稱為lhs_3，lhs_4 ，lhs_5和lhs_6。 任何幫助表示贊賞

Answer 1

我找到了一種解決方法，可以完成這項工作：

tmp.df.lhs.denorm.art <- data.table(rules = character(),
                                         support = numeric(),
                                         confidence = numeric(),
                                         lift = numeric(),
                                         rule.id = integer(),
                                        lhs_1 = character(),
                                        lhs_2 = character(),
                                        lhs_3 = character(),
                                        lhs_4 = character(),
                                        lhs_5 = character(),
                                        lhs_6 = character()
                                      )
  tmp.df.lhs.denorm.complete <- rbindlist(list(tmp.df.lhs.denorm, tmp.df.lhs.denorm.art), fill=TRUE)