Update README, vignette.

NEWS.md

@@ -4,9 +4,11 @@
   providers (@fmgithub2017, #3 github).
 * New function `rdb_dimensions()` to request the list of the dimensions of
   the available datasets of the providers (@fmgithub2017, #3 github).
+* New function `rdb_series()` to request the list of the series of
+  the available datasets of the providers (@fmgithub2017, #3 github).
 * Add a clearer error message to the function to_xts() in README (Martin
   Feldkircher, 20200326 email).
-* Update vignette for `rdb_datasets()` and `rdb_dimensions()`.
+* Update vignette for `rdb_datasets()`, `rdb_dimensions()` and `rdb_series()`.
 
 # rdbnomics 0.5.2
 

R/rdb_datasets.R

@@ -69,9 +69,9 @@ rdb_datasets <- function(
   # }, simplify = FALSE)
 
   # Additionals arguments
-  progress_bar = TRUE
+  progress_bar <- TRUE
   if (length(list(...)) > 0) {
-    tmp_progress_bar = list(...)$progress_bar
+    tmp_progress_bar <- list(...)$progress_bar
     if (!is.null(tmp_progress_bar)) {
       progress_bar <- tmp_progress_bar
     }

R/rdb_dimensions.R

@@ -71,9 +71,9 @@ rdb_dimensions <- function(
   ...
 ) {
   # Additionals arguments
-  progress_bar = TRUE
+  progress_bar <- TRUE
   if (length(list(...)) > 0) {
-    tmp_progress_bar = list(...)$progress_bar
+    tmp_progress_bar <- list(...)$progress_bar
     if (!is.null(tmp_progress_bar)) {
       progress_bar <- tmp_progress_bar
     }

R/rdb_series.R

@@ -75,24 +75,33 @@ rdb_series <- function(
   ...
 ) {
   # Additionals arguments
-  progress_bar = TRUE
+  progress_bar <- TRUE
   if (length(list(...)) > 0) {
-    tmp_progress_bar = list(...)$progress_bar
+    tmp_progress_bar <- list(...)$progress_bar
     if (!is.null(tmp_progress_bar)) {
       progress_bar <- tmp_progress_bar
     }
   }
   check_argument(progress_bar, "logical")
 
-  only_first_two = FALSE
+  only_first_two <- FALSE
   if (length(list(...)) > 0) {
-    tmp_only_first_two = list(...)$only_first_two
+    tmp_only_first_two <- list(...)$only_first_two
     if (!is.null(tmp_only_first_two)) {
       only_first_two <- tmp_only_first_two
     }
   }
   check_argument(only_first_two, "logical")
 
+  only_number_series <- FALSE
+  if (length(list(...)) > 0) {
+    tmp_only_number_series <- list(...)$only_number_series
+    if (!is.null(tmp_only_number_series)) {
+      only_number_series <- tmp_only_number_series
+    }
+  }
+  check_argument(only_number_series, "logical")
+
   # All providers
   if (is.null(provider_code)) {
     provider_code <- rdb_providers(
@@ -146,6 +155,10 @@ rdb_series <- function(
         limit <- DBlist$series$limit
         num_found <- DBlist$series$num_found
 
+        if (only_number_series) {
+          return(data.table(Number_of_series = num_found))
+        }
+
         if (verbose) {
           if (getOption("rdbnomics.progress_bar_series") & progress_bar) {
             cat("\n")

README.md

@@ -134,6 +134,16 @@ provider, if you define `simplify = TRUE`, then the result will be a named list
 df_dimensions <- rdb_dimensions(provider_code = "IMF", dataset_code = "WEO", simplify = TRUE)
 ```
 
+## Fetch the number of series of available datasets of a provider
+```r
+# Example for the dataset WEOAGG of the IMF:
+rdb_series(provider_code = "IMF", dataset_code = "WEOAGG", simplify = TRUE)
+```
+
+:warning: We ask the user to use this function parsimoniously because there are a huge amount
+of series per dataset. Please only fetch for one dataset if you need it or
+visit the website [https://db.nomics.world](https://db.nomics.world).  
+
 ## Proxy configuration or connection error `Could not resolve host`
 When using the function `rdb`, you may come across the following error:
 ```r

vignettes/rdbnomics.Rmd

@@ -688,7 +688,7 @@ You can measure the vast extent of datasets gathered by
 [DBnomics](https://db.nomics.world) by downloading all the possible
 dimensions. To do this, you have to set the arguments
 `provider_code` and `dataset_code` to `NULL`.  
-Warning : it's relatively long to run and heavy to show so we display
+<b><font color='red'>&#9888;</font></b> it's relatively long to run and heavy to show so we display
 the first 100.
 ```{r, eval = FALSE}
 options(rdbnomics.progress_bar_datasets = TRUE)
@@ -726,6 +726,31 @@ rdbnomics:::rdbnomics_df022 %>%
 #   rbindlist(idcol = "Provider")
 ```
 
+# Fetch the number of series of available datasets of a provider
+
+You can download the list of series, and especially their codes, of a dataset's
+provider by using the function `rdb_series`. The result is a nested named list
+with a `data.table` at the end of each branch. If you define `simplify = TRUE`,
+then the result will be a named list `data.table` not a nested named list.  
+For example, for the **IMF** provider and the dataset **WEO**, the command is:
+```{r, eval = FALSE}
+rdb_series(provider_code = "IMF", dataset_code = "WEO", simplify = TRUE)
+```
+```{r, eval = TRUE, echo = FALSE}
+rdbnomics:::rdbnomics_df023 %>%
+  display_table()
+```
+
+<b><font color='red'>&#9888;</font></b> We ask the user to use this function parsimoniously because there are a huge amount
+of series per dataset. Please only fetch for one dataset if you need it or
+visit the website [https://db.nomics.world](https://db.nomics.world).  
+For example, for the **IMF** provider, the number of series is:
+```{r, eval = TRUE, echo = FALSE}
+rdbnomics:::rdbnomics_df024 %>%
+  .[order(-`Number of series`)] %>%
+  display_table()
+```
+
 # Proxy configuration or connection error `Could not resolve host`
 
 When using the function `rdb`, you may come across the following error: