Week 8: Apply it to your data 7

Import your data

# csv file
mydata <- read_csv('https://raw.githubusercontent.com/rfordatascience/tidytuesday/main/data/2025/2025-07-01/weekly_gas_prices.csv')

## Rows: 22360 Columns: 5
## ── Column specification ────────────────────────────────────────────────────────
## Delimiter: ","
## chr  (3): fuel, grade, formulation
## dbl  (1): price
## date (1): date
## 
## ℹ Use `spec()` to retrieve the full column specification for this data.
## ℹ Specify the column types or set `show_col_types = FALSE` to quiet this message.

Pivoting

long to wide form

mydata_wide <- mydata %>%
  pivot_wider(
    names_from = grade,
    values_from = price
  )

### wide to long form
mydata_long <- mydata_wide %>%
  pivot_longer(
    cols = -c(date, fuel, formulation),
    names_to  = "grade",
    values_to = "price",
    values_drop_na = TRUE
  )

Separating and Uniting

Separate a column

mydata_sep <- mydata %>%
    
    separate(col = formulation, into = c("all", "na"))

## Warning: Expected 2 pieces. Missing pieces filled with `NA` in 19672 rows [1, 2, 3, 4,
## 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, ...].

Unite two columns

mydata_sep %>%
    
    unite(col = "formulation", all:na, sep = "/")

## # A tibble: 22,360 × 5
##    date       fuel     grade   formulation     price
##    <date>     <chr>    <chr>   <chr>           <dbl>
##  1 1990-08-20 gasoline regular all/NA           1.19
##  2 1990-08-20 gasoline regular conventional/NA  1.19
##  3 1990-08-27 gasoline regular all/NA           1.25
##  4 1990-08-27 gasoline regular conventional/NA  1.25
##  5 1990-09-03 gasoline regular all/NA           1.24
##  6 1990-09-03 gasoline regular conventional/NA  1.24
##  7 1990-09-10 gasoline regular all/NA           1.25
##  8 1990-09-10 gasoline regular conventional/NA  1.25
##  9 1990-09-17 gasoline regular all/NA           1.27
## 10 1990-09-17 gasoline regular conventional/NA  1.27
## # ℹ 22,350 more rows

Missing Values

mydata %>% 
    filter(!is.na(price))

## # A tibble: 22,360 × 5
##    date       fuel     grade   formulation  price
##    <date>     <chr>    <chr>   <chr>        <dbl>
##  1 1990-08-20 gasoline regular all           1.19
##  2 1990-08-20 gasoline regular conventional  1.19
##  3 1990-08-27 gasoline regular all           1.25
##  4 1990-08-27 gasoline regular conventional  1.25
##  5 1990-09-03 gasoline regular all           1.24
##  6 1990-09-03 gasoline regular conventional  1.24
##  7 1990-09-10 gasoline regular all           1.25
##  8 1990-09-10 gasoline regular conventional  1.25
##  9 1990-09-17 gasoline regular all           1.27
## 10 1990-09-17 gasoline regular conventional  1.27
## # ℹ 22,350 more rows