For循环提取数据

Question

我有这些变量的数据集（分支、项目、销售、库存）我需要创建一个 for 循环来提取具有以下内容的数据

具有相同的项目
1-不同的分支
2-它的销售额高于股票

并将结果保存在数据框中 我使用的代码是

trials <- sample_n(Data_with_stock,1000)

for (i in  1:nrow(trials)) 
{
if(trials$sales[i] >  trials$stock[i] & trials$item[i] ==  trials$item[i+1] & trials$branch[i] !=  trials$branch[i+1])

{s <-data.frame( (trials$NAME[i])
  ,(trials$branch[i]))
} 

}

Answer 1

建议您使用 dplyr 库，安装后考虑“df”是您的数据集，对问题 1 和 2 使用以下命令

问题 1

question_one = df %>% group_by(Item) %>% summarise(No_of_branches = n_distinct(Branch))

items_with_more_than_one_branch = question_one[which(question_one$No_of_branches>1)"Item"]

问题2：同样，

question_two = df %>% group_by(Item) %>% summarise(Stock_Val = sum(Stock), Sales_Val = sum(Sales))

item_with_sales_greater_than_stock = question_two[which(question_two$Sales > question_two$Stock),"Item"]

没有 dplyr 无法解决，但是建议，如果尚未使用，dplyr 将始终对数据处理有用

Answer 2

因为你只是想修复你的代码：

您错过了在您的代码中设置一个=。

用途：

trials <- sample_n(Data_with_stock,1000)
# next you need first to define s used in your loop
s <- array(NA, dim = c(1,2)) # as you only save 2 things in s per iteration

for (i in  1:nrow(trials)) {
# but I dont get why you compare the second condition.

if(trials$sales[i] >  trials$stock[i] & trials$item[i] ==  trials$item[i] & trials$branch[i] !=  trials$branch[i+1]) {

s[i,] <- cbind(trials$NAME[i], trials$branch[i])
} else {
s[i,] <- NA # just to have no problem with the index i, you can delete the one with na afterwards with na.omit()
}