如何将特定行转换为R中的列？

Question

I have a df in R of only one column of food ratings from amazon.

head(food_ratings)
          product.productId..B001E4KFG0
1         review/userId: A3SGXH7AUHU8GW
2        review/profileName: delmartian
3               review/helpfulness: 1/1
4                     review/score: 5.0
5               review/time: 1303862400
6 review/summary: Good Quality Dog Food

The rows repeat themselves, so that rows 7 through 12 have the same information regarding another user(row 7). This pattern is repeated many times.

Therefore, I need to have every group of 6 rows distributed in one row with 6 columns, so that later I can subset, for instance, the review/summary according to their review/score.

I'm using RStudio 1.0.143

EDIT: I was asked to show the output of dput(head(food_ratings, 24)) but it was too big regardless of the number used. Thanks a lot

Answer 1

I have taken your data and added 2 more fake users to it. Using tidyr and dplyr you can create new columns and collapse the data into a nice data.frame. You can use select from dplyr to drop the id column if you don't need it or to rearrange the order of the columns.

library(tidyr)
library(dplyr)

df %>% 
  separate(product.productId..B001E4KFG0, into = c("details", "data"), sep = ": ") %>% 
  mutate(details = sub("review/ ", "", details)) %>% 
  group_by(details) %>% 
  mutate(id = row_number()) %>% 
  spread(details, data)


# A tibble: 3 x 7
     id helpfulness profileName score summary                 time       userId        
  <int> <chr>       <chr>       <chr> <chr>                   <chr>      <chr>         
1     1 1/1         delmartian  5.0   Good Quality Dog Food   1303862400 A3SGXH7AUHU8GW
2     2 1/1         martian2    1.0   Good Quality Snake Food 1303862400 123456        
3     3 2/5         martian3    5.0   Good Quality Cat Food   1303862400 123654  

data:

df <- structure(list(product.productId..B001E4KFG0 = c("review/userId: A3SGXH7AUHU8GW", 
"review/profileName: delmartian", "review/helpfulness: 1/1", 
"review/score: 5.0", "review/time: 1303862400", "review/summary: Good Quality Dog Food", 
"review/userId: 123456", "review/profileName: martian2", "review/helpfulness: 1/1", 
"review/score: 1.0", "review/time: 1303862400", "review/summary: Good Quality Snake Food", 
"review/userId: 123654", "review/profileName: martian3", "review/helpfulness: 2/5", 
"review/score: 5.0", "review/time: 1303862400", "review/summary: Good Quality Cat Food"
)), class = "data.frame", row.names = c(NA, -18L))