Set Symbol value for symbols with no data

Alphavantage returns NULL for all the columns of data for requests on
invalid symbols. We need to set the Symbol column to the value of the
symbol input in order to return a row of NA for the symbol in the
results, as we do for other getQuote() methods.

See #296.

R/getQuote.R

@@ -304,29 +304,37 @@ getQuote.av <- function(Symbols, api.key, ...) {
 
   # Function to process each quote response
   quote2df <-
-    function(response, map)
+    function(response, map, symbol)
   {
     # Expected response structure
     qres <- setNames(vector("list", nrow(map)), map[["av.names"]])
 
-    elem <- function(el)
+    elem <- function(el, isnum)
     {
-      # process numeric columns
       res <- NA_real_
       if (!is.null(el)) {
-        haspct <- grepl("%", el, fixed = TRUE)
-        if (haspct) {
-          el <- sub("%", "", el, fixed = TRUE)
-          res <- as.numeric(el) / 100
+        if (isnum) {
+          # process numeric columns
+          haspct <- grepl("%", el, fixed = TRUE)
+          if (haspct) {
+            el <- sub("%", "", el, fixed = TRUE)
+            res <- as.numeric(el) / 100
+          } else {
+            res <- as.numeric(el)
+          }
         } else {
-          res <- as.numeric(el)
+          res <- el
         }
       }
       res
     }
     tmp <- modifyList(qres, response)
-    tonum <- map[["is.number"]]
-    tmp[tonum] <- lapply(tmp[tonum], elem)
+    tmp <- Map(elem, el = tmp, isnum = map[["is.number"]])
+
+    # populate Symbol column for symbols missing quotes
+    if (is.na(tmp[["01. symbol"]])) {
+      tmp[["01. symbol"]] <- symbol
+    }
 
     data.frame(tmp, stringsAsFactors = FALSE)
   }
@@ -348,7 +356,7 @@ getQuote.av <- function(Symbols, api.key, ...) {
               call. = FALSE, immediate. = TRUE)
     } else {
       resp <- resp[[1]]  # resp$`Global Quote`
-      qlist[[Symbol]] <- quote2df(resp, map)
+      qlist[[Symbol]] <- quote2df(resp, map, Symbol)
     }
   }