eval_vroom <- FALSE if(Sys.getenv("GLOBAL_EVAL") != "") eval_vroom <- Sys.getenv("GLOBAL_EVAL")
library(vroom) library(fs) library(purrr) library(dplyr)
vroom
vroom
basicsLoad data into R using vroom
Load the vroom()
library
r
library(vroom)
Use the vroom()
function to read the transactions_1.csv file from the /usr/share/class/files folder
r
vroom("/usr/share/class/files/transactions_1.csv")
Use the id
argument to add the file name to the data frame. Use file_name as the argument's value
```r
```
Load the prior command into a variable called vr_transactions
```r
```
Load the file spec into a variable called vr_spec
, using the spec()
command
```r
vr_spec <- spec(vr_transactions)
vr_spec ```
Load the fs
and dplyr
libraries
r
library(fs)
library(dplyr)
List files in the /usr/share/class/files folder using the dir_ls()
function
r
dir_ls("/usr/share/class/files")
In the dir_ls()
function, use the glob
argument to pass a wildcard to list CSV files only. Load to a variable named files
```r
```
Pass the files
variable to vroom
. Set the n_max
argument to 1,000 to limit the data load for now
```r
```
Add a col_types
argument with vr_specs
as its value
```r
```
Use the col_select
argument to pass a list
object containing the following variables: order_id, date, customer_name, and price
```r
```
For files that are too large to have in memory, keep a summarization
Use a for()
loop to print the content of each vector inside files
r
for(i in seq_along(files)) {
print(files[i])
}
Switch the print()
command with the vroom
command, using the same arguments, except the file name. Use the files
variable. Load the results into a variable called transactions
.
```r
for(i in seq_along(files)) {
} ```
Group transactions
by order_id
and get the total of price
and the number of records. Name them total_sales
and no_items
respectively. Name the new variable orders
```r
for(i in seq_along(files)) {
} ```
Define the orders
variable as NULL
prior to the for loop and add a bind_rows()
step to orders
to preserve each summarized view.
```r
orders <- NULL
for(i in seq_along(files)) {
} ```
Remove the transactions
variable at the end of each cycle
```r
orders <- NULL
for(i in seq_along(files)) {
} ```
Preview the orders
variable
r
orders
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