在 R 如何从从标准输入读取值创建数据帧

Question

How to read the below stdin values and create a data frame in R. Here stdin values are dynamic

PrimeSuperMarket
4
Choclate
Jam
Milk
Rice

Line 1 denotes ShopName

Line 2 denotes NumberOfItems Planning to purchase

Line 3 to 7 : Item Type

Line No 3 to n is dynamic that depends upon line no 2 value. If value is passed as 5 in line 2. Line 3 to Line 8 will be there, So totally 5 values will be entered.

My Expected output is

Answer 1

If your input file is called input.txt you can read it with readLines and create a dataframe like so -

val <- readLines('input.txt')
shopName <- val[1]
Item <- val[3:(3 + as.numeric(val[2]) - 1)]
# Or you can read everything removing 1st 2 values
#Item <- val[-c(1:2)]
data.frame(shopName, Item)


#          shopName     Item
#1 PrimeSuperMarket Choclate
#2 PrimeSuperMarket      Jam
#3 PrimeSuperMarket     Milk
#4 PrimeSuperMarket     Rice