Add demo for retrieving book titles from DeLiKo@DNB

Change-Id: I96fcdf0593fe5e8e8b29ba70b9c08d1a62f72a80
diff --git a/demo/00Index b/demo/00Index
index 8a1200f..537de21 100644
--- a/demo/00Index
+++ b/demo/00Index
@@ -16,3 +16,4 @@
 pluralGenderVariants            Plot frequencies of the plural gender variants of a word in the core corpus of the Council for German Orthography (OKK) over time.
 adjectiveCollocates             Shows adjective collocates of 'Gendern'.
 relativeTextpositionBoxplot     Plot the relative text positions of a some adverbs as highcharter boxplot.
+retrieveTitlesFromDeliko				Retrieves and shows all titles from novels of a chosen genre in the DeLiKo@DNB German fiction corpus.
diff --git a/demo/retrieveTitlesFromDeliko.R b/demo/retrieveTitlesFromDeliko.R
new file mode 100644
index 0000000..800ee01
--- /dev/null
+++ b/demo/retrieveTitlesFromDeliko.R
@@ -0,0 +1,29 @@
+library(RKorAPClient)
+library(tidyverse)
+
+VC = "textTypeRef = /Arzt.*/" # virtual corpus with just doctor novels etc.
+
+query <- KorAPConnection("https://korap.dnb.de", verbose = TRUE) |>
+	corpusQuery(
+		"<base/s=t>",	# this finds each text once
+		vc = VC,
+		fields = c(
+			"textSigle",
+			"title",
+			"subTitle"
+			#		"author",
+			#		"textType",
+			#		"textTypeRef",
+			#		"publisher",
+			#		"pubDate",
+			#		"pubPlace",
+			#		"ISBN",
+			#		"URN"
+		)
+	) |>
+	fetchAll()
+
+df <- query@collectedMatches |>
+	select(-c("matchStart", "matchEnd"))
+
+View(df)