小编Ben*_*son的帖子

我依靠矢量回收来用模拟数据填充 R 数据框，但行为与预期不符。

我可以成功运行它：

store.df <- data.frame(matrix(NA, ncol=5, nrow=2080))
names(store.df)<-c("storeNum", "upc_id", "Week_id", "weekday_id", "units")
sn<-c(60, 89, 105, 170, 1240)
store.df$storeNum <- sn
wid<-c(201531,201532,201533,201534,201535,201536,201537,201538)
store.df$Week_id <- wid

为了达成这个：

summary(store.df)

        storeNum       upc_id           Week_id       weekday_id      units        
 Min.   :  60.0   Mode:logical   Min.   :201531   Mode:logical   Mode:logical  
 1st Qu.:  89.0   NA's:2080      1st Qu.:201533   NA's:2080      NA's:2080     
 Median : 105.0                  Median :201535                                
 Mean   : 332.8                  Mean   :201535                                
 3rd Qu.: 170.0                  3rd Qu.:201536                                
 Max.   :1240.0                  Max.   :201538 

但是，如果我运行此处看到的最后两行：

store.df <- data.frame(matrix(NA, ncol=5, nrow=2080))
names(store.df)<-c("storeNum", "upc_id", "Week_id", "weekday_id", "units")
sn<-c(60, …