Update and rename xts.tex to xts.md

xts.tex → xts.md

@@ -1,43 +1,47 @@
 %%- https://cran.r-project.org/web/packages/xts/vignettes/xts.pdf
 
-\section*{The structure of xts}
+## The structure of xts
 To understand a bit more of what an xts object can do, it may be beneficial to
 know what an xts object is. This section is intended to provide a quick overview
 of the basics of the class, as well as what features make it unique.
-%--------------------------------------------%
-2.1 It’s a zoo in here
+
+#### 2.1 It’s a zoo in here
 At the core of an xts object is a zoo object from the package of the same
 name. Simplified, this class contains an array of values comprising your data
 (often in matrix form) and an index attribute to provide information about the
 data’s ordering. Most of the details surrounding zoo objects apply equally to
 xts. As it would be redundent to simply retell the excellent introductory zoo
 vignette, the reader is advised to read, absorb, and re-read that documentation
-to best understand the power of this class. The authors of the xts package
+to best understand the power of this class. 
+
+The authors of the xts package
 recognize that zoo’s strength comes from its simplicity of use, as well as its
 overall flexibility. What motivated the xts extension was a desire to have even
 more flexibility, while imposing reasonable constraints to make this class into a
 true time-based one.
 
-%--------------------------------------------%
-2.2 xts modifications
+#### 2.2 xts modifications
 Objects of class xts differ from objects of class zoo in three key ways: the use
 of formal time-based classes for indexing, internal xts properties, and perhaps
 most uniquely — user-added attributes.
-\subsection{*True time-based indexes}
+
+#### True time-based indexes
 To allow for functions that make use of xts objects as a general time-series
 object - it was necessary to impose a simple rule on the class. The index of each
 xts object must be of a known and supported time or date class. At present
 this includes any one of the following - Date, POSIXct, chron, yearmon, yearqtr,
-or timeDate. The relative merits of each are left to the judgement of the user,
+or timeDate. 
+The relative merits of each are left to the judgement of the user,
 though the first three are expected to be sufficient for most applications.
 Internal attributes: .CLASS, .ROWNAMES, etc.
+
 In order for one major feature of the xts class to be possible - the conversion and
 re-conversion of classes to and from xts - certain elements must be preserved
 within the converted object. These are for internal use, and as such require
 little further explanation in an introductory document. Interested readers are
 invited to examine the source as well as read the developer documentation.
-%========================================================%
-\subsection{xtsAttributes}
+
+#### xtsAttributes
 This is what makes the xts class an extensible time-series class. Arbitrary attributes
 may be assigned and removed from the object without causing issues
 with the data’s display or otherwise. Additionally this is where other class specific