1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
|
## ----include=FALSE------------------------------------------------------------
options(rdf_print_format = "nquads")
is_linux <- Sys.info()["sysname"] == "Linux"
knitr::opts_chunk$set(eval=is_linux)
## ----message = FALSE, warning=FALSE-------------------------------------------
library(rdflib)
library(dplyr)
library(tidyr)
library(tibble)
library(jsonld)
## -----------------------------------------------------------------------------
car_triples <-
mtcars %>%
rownames_to_column("Model") %>%
gather(attribute,measurement, -Model)
## ----echo=FALSE---------------------------------------------------------------
DT::datatable(car_triples)
## -----------------------------------------------------------------------------
car_triples <-
mtcars %>%
rownames_to_column("Model") %>%
rowid_to_column("subject") %>%
gather(predicate, object, -subject)
## ----echo=FALSE---------------------------------------------------------------
DT::datatable(car_triples)
## -----------------------------------------------------------------------------
iris_triples <- iris %>%
rowid_to_column("subject") %>%
gather(key = predicate, value = object, -subject)
## ----echo=FALSE---------------------------------------------------------------
DT::datatable(iris_triples)
## -----------------------------------------------------------------------------
iris_triples <- iris %>%
rowid_to_column("subject") %>%
mutate(subject = paste0("http://example.com/", "iris#", subject)) %>%
gather(key = predicate, value = object, -subject)
## ----echo=FALSE---------------------------------------------------------------
DT::datatable(iris_triples)
## ----mesage = FALSE-----------------------------------------------------------
iris_triples <- iris %>%
rowid_to_column("subject") %>%
mutate(subject = paste0("http://example.com/", "iris#", subject)) %>%
gather(key = predicate, value = object, -subject) %>%
mutate(predicate = paste0("http://example.com/", "iris#", predicate))
## ----echo=FALSE---------------------------------------------------------------
DT::datatable(iris_triples)
## -----------------------------------------------------------------------------
rdf <- rdf()
## -----------------------------------------------------------------------------
base <- paste0("http://example.com/", "iris#")
rdf %>%
rdf_add(subject = paste0(base, "obs1"),
predicate = paste0(base, "Sepal.Length"),
object = 5.1)
rdf
## -----------------------------------------------------------------------------
rdf <- rdf()
rdf %>% rdf_add("",
"iris:Sepal.Length",
object = 5.1)
rdf
## -----------------------------------------------------------------------------
rdf_serialize(rdf, "rdf.nq", format = "nquads")
## -----------------------------------------------------------------------------
doc <- system.file("extdata/example.rdf", package="redland")
rdf <- rdf_parse(doc, format = "rdfxml")
rdf
## -----------------------------------------------------------------------------
options(rdf_print_format = "rdfxml")
rdf
## -----------------------------------------------------------------------------
options(rdf_print_format = "turtle")
rdf
## -----------------------------------------------------------------------------
options(rdf_print_format = "jsonld")
rdf
## -----------------------------------------------------------------------------
rdf_serialize(rdf, "example.json", "jsonld") %>%
jsonld_compact(context = '{"@vocab": "http://purl.org/dc/elements/1.1/"}')
## -----------------------------------------------------------------------------
ex <- system.file("extdata/person.json", package="rdflib")
cat(readLines(ex), sep = "\n")
#jsonld_compact(ex, "{}")
## -----------------------------------------------------------------------------
options(rdf_print_format = "nquads")
rdf <- rdf_parse(ex, "jsonld")
rdf
## -----------------------------------------------------------------------------
jsonld_flatten(ex, context = "https://schema.org/")
## -----------------------------------------------------------------------------
jsonld_flatten(ex) %>%
jsonld_frame('{"@type": "https://schema.org//Person"}') %>%
jsonld_compact(context = "https://schema.org/")
## -----------------------------------------------------------------------------
as_rdf.list <- function(x, context = "https://schema.org/"){
if(length(x) == 1) x <- x[[1]]
x[["@context"]] <- context
json <- jsonlite::toJSON(x, pretty = TRUE, auto_unbox = TRUE, force = TRUE)
rdflib::rdf_parse(json, "jsonld")
}
## -----------------------------------------------------------------------------
context <- list("https://schema.org/",
list(schema = "https://schema.org//",
given = "givenName",
family = "familyName",
title = "name",
year = "datePublished",
note = "softwareVersion",
comment = "identifier",
role = "http://www.loc.gov/marc/relators/relaterm.html"))
## -----------------------------------------------------------------------------
options(rdf_print_format = "nquads") # go back to the default
R <- citation("rdflib")
rdf <- as_rdf.list(R, context)
rdf
## -----------------------------------------------------------------------------
#source(system.file("examples/as_rdf.R", package="rdflib"))
source(system.file("examples/tidy_schema.R", package="rdflib"))
## Testing: Digest some data.frames into RDF and extract back
cars <- mtcars %>% rownames_to_column("Model")
x1 <- as_rdf(iris, NULL, "iris:")
x2 <- as_rdf(cars, NULL, "mtcars:")
rdf <- c(x1,x2)
## -----------------------------------------------------------------------------
sparql <-
'SELECT ?Species ?Sepal_Length ?Sepal_Width ?Petal_Length ?Petal_Width
WHERE {
?s <iris:Species> ?Species .
?s <iris:Sepal.Width> ?Sepal_Width .
?s <iris:Sepal.Length> ?Sepal_Length .
?s <iris:Petal.Length> ?Petal_Length .
?s <iris:Petal.Width> ?Petal_Width
}'
iris2 <- rdf_query(rdf, sparql)
## ----echo=FALSE---------------------------------------------------------------
DT::datatable(iris2)
## -----------------------------------------------------------------------------
sparql <- tidy_schema("Species", "Sepal.Length", "Sepal.Width", prefix = "iris")
rdf_query(rdf, sparql)
## ----include=FALSE------------------------------------------------------------
unlink("rdf.nq")
unlink("example.json")
|
