update to show current / simplified attributes use

Author: eddelbuettel

_posts/2013-01-12-getting-attributes-for-xts-example.md

@@ -25,7 +25,7 @@ using namespace Rcpp;
 
 // [[Rcpp::export]]
 std::vector<std::string> xtsAttributes(NumericMatrix X) {
-    std::vector<std::string> nm = RObject(X).attributeNames();
+    std::vector<std::string> nm = X.attributeNames();
     return nm;
 }
 {% endhighlight %}
@@ -35,38 +35,38 @@ A first example simply creates a random `xts` object of twenty observations.
 We then examine the set of attributes and return it in a first program.
 
 {% highlight r %}
-  suppressMessages(library(xts))
-  set.seed(42)
-  n <- 20
-  Z <- xts(100+cumsum(rnorm(n)), order.by=ISOdatetime(2013,1,12,20,21,22) + 60*(1:n))
-  xtsAttributes(Z)
+    suppressMessages(library(xts))
+    set.seed(42)
+    n <- 20
+    Z <- xts(100+cumsum(rnorm(n)), order.by=ISOdatetime(2013,1,12,20,21,22) + 60*(1:n))
+    xtsAttributes(Z)
 {% endhighlight %}
 
 
 
 <pre class="output">
-[1] "dim"         "index"       "class"       ".indexCLASS" "tclass"     
-[6] ".indexTZ"    "tzone"      
+[1] &quot;dim&quot;         &quot;index&quot;       &quot;class&quot;       &quot;.indexCLASS&quot; &quot;tclass&quot;     
+[6] &quot;.indexTZ&quot;    &quot;tzone&quot;      
 </pre>
 
 
 The same result is seen directly in R:
 
 {% highlight r %}
-  names(attributes(Z))
+    names(attributes(Z))
 {% endhighlight %}
 
 
 
 <pre class="output">
-[1] "dim"         "index"       "class"       ".indexCLASS" "tclass"     
-[6] ".indexTZ"    "tzone"      
+[1] &quot;dim&quot;         &quot;index&quot;       &quot;class&quot;       &quot;.indexCLASS&quot; &quot;tclass&quot;     
+[6] &quot;.indexTZ&quot;    &quot;tzone&quot;      
 </pre>
 
 
 
 {% highlight r %}
-  all.equal(xtsAttributes(Z), names(attributes(Z)))
+    all.equal(xtsAttributes(Z), names(attributes(Z)))
 {% endhighlight %}
 
 
@@ -84,31 +84,34 @@ we have a `Datetime` object so we can instantiate it at the C++ level.
 {% highlight cpp %}
 // [[Rcpp::export]]
 DatetimeVector xtsIndex(NumericMatrix X) {
-    DatetimeVector v(NumericVector(RObject(X).attr("index")));
+    DatetimeVector v(NumericVector(X.attr("index")));
     return v;
 }
 {% endhighlight %}
 
 
 {% highlight r %}
-  xtsIndex(Z)
+    xtsIndex(Z)
 {% endhighlight %}
 
 
 
 <pre class="output">
- [1] "2013-01-12 20:22:22 CST" "2013-01-12 20:23:22 CST"
- [3] "2013-01-12 20:24:22 CST" "2013-01-12 20:25:22 CST"
- [5] "2013-01-12 20:26:22 CST" "2013-01-12 20:27:22 CST"
- [7] "2013-01-12 20:28:22 CST" "2013-01-12 20:29:22 CST"
- [9] "2013-01-12 20:30:22 CST" "2013-01-12 20:31:22 CST"
-[11] "2013-01-12 20:32:22 CST" "2013-01-12 20:33:22 CST"
-[13] "2013-01-12 20:34:22 CST" "2013-01-12 20:35:22 CST"
-[15] "2013-01-12 20:36:22 CST" "2013-01-12 20:37:22 CST"
-[17] "2013-01-12 20:38:22 CST" "2013-01-12 20:39:22 CST"
-[19] "2013-01-12 20:40:22 CST" "2013-01-12 20:41:22 CST"
+ [1] &quot;2013-01-12 20:22:22 CST&quot; &quot;2013-01-12 20:23:22 CST&quot;
+ [3] &quot;2013-01-12 20:24:22 CST&quot; &quot;2013-01-12 20:25:22 CST&quot;
+ [5] &quot;2013-01-12 20:26:22 CST&quot; &quot;2013-01-12 20:27:22 CST&quot;
+ [7] &quot;2013-01-12 20:28:22 CST&quot; &quot;2013-01-12 20:29:22 CST&quot;
+ [9] &quot;2013-01-12 20:30:22 CST&quot; &quot;2013-01-12 20:31:22 CST&quot;
+[11] &quot;2013-01-12 20:32:22 CST&quot; &quot;2013-01-12 20:33:22 CST&quot;
+[13] &quot;2013-01-12 20:34:22 CST&quot; &quot;2013-01-12 20:35:22 CST&quot;
+[15] &quot;2013-01-12 20:36:22 CST&quot; &quot;2013-01-12 20:37:22 CST&quot;
+[17] &quot;2013-01-12 20:38:22 CST&quot; &quot;2013-01-12 20:39:22 CST&quot;
+[19] &quot;2013-01-12 20:40:22 CST&quot; &quot;2013-01-12 20:41:22 CST&quot;
 </pre>
 
 
 Further operations such as subsetting based on the datetime vector
 or adjustments to time zones are left as an exercise.
+
+Edited on 2014-03-28 to reflect updated / simpliefied attributes functions.
+

src/2013-01-12-getting-attributes-for-xts-example.cpp

@@ -23,7 +23,7 @@ using namespace Rcpp;
 
 // [[Rcpp::export]]
 std::vector<std::string> xtsAttributes(NumericMatrix X) {
-    std::vector<std::string> nm = RObject(X).attributeNames();
+    std::vector<std::string> nm = X.attributeNames();
     return nm;
 }
 
@@ -33,20 +33,20 @@ std::vector<std::string> xtsAttributes(NumericMatrix X) {
  */
 
 /*** R
-  suppressMessages(library(xts))
-  set.seed(42)
-  n <- 20
-  Z <- xts(100+cumsum(rnorm(n)), order.by=ISOdatetime(2013,1,12,20,21,22) + 60*(1:n))
-  xtsAttributes(Z)
+    suppressMessages(library(xts))
+    set.seed(42)
+    n <- 20
+    Z <- xts(100+cumsum(rnorm(n)), order.by=ISOdatetime(2013,1,12,20,21,22) + 60*(1:n))
+    xtsAttributes(Z)
 */
 
 /**
  * The same result is seen directly in R:
  */
 
 /*** R
-  names(attributes(Z))
-  all.equal(xtsAttributes(Z), names(attributes(Z)))
+    names(attributes(Z))
+    all.equal(xtsAttributes(Z), names(attributes(Z)))
 */
 
 
@@ -60,16 +60,20 @@ std::vector<std::string> xtsAttributes(NumericMatrix X) {
 
 // [[Rcpp::export]]
 DatetimeVector xtsIndex(NumericMatrix X) {
-    DatetimeVector v(NumericVector(RObject(X).attr("index")));
+    DatetimeVector v(NumericVector(X.attr("index")));
     return v;
 }
 
 /*** R
-  xtsIndex(Z)
+    xtsIndex(Z)
 */
 
 /**
  * Further operations such as subsetting based on the datetime vector
  * or adjustments to time zones are left as an exercise.
  */
 
+/**
+ * Edited on 2014-03-28 to reflect updated / simpliefied attributes functions.
+ *
+ */