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ExpressionML (.xml)

Background & Context

    • MIME type: text/xmlWolfram Language ExpressionML format.
    • Represents an arbitrary Wolfram Language expression as XML.
    • Used for the exchange of general expressions between the Wolfram System and other applications.
    • Plain text file, normally encoded as UTF-8.
    • Developed in 2002 by Wolfram Research.

Import & Export

  • Import["file.xml"] imports an ExpressionML file and returns an expression.
  • Export["file.xml",expr,"ExpressionML"] exports an arbitrary expression to XML.
  • Import["file.xml"] reads an XML file that holds ExpressionML data and converts it to the corresponding Wolfram Language expression.
  • When reading XML, Import automatically recognizes the ExpressionML format. Generic XML content will be imported as an XMLObject expression.
  • Export["file.xml",expr,"ExpressionML"] converts an arbitrary Wolfram Language expression to the corresponding ExpressionML data structure and writes it to an XML file.
  • Export["file.xml",XMLObject[…]] converts a symbolic XML expression to generic XML.
  • Import["file.xml",elem] imports the specified element from an ExpressionML file.
  • Import["file.xml",{{elem1,elem2,…}}] imports multiple elements.
  • The import format can be specified with Import["file","ExpressionML"] or Import["file",{"ExpressionML",elem,…}].
  • Export["file.xml",expr,elem] creates an ExpressionML file by treating expr as specifying element elem.
  • Export["file.xml",{expr1,expr2,…},{{elem1,elem2,…}}] treats each expri as specifying the corresponding elemi.
  • Export["file.xml",expr,opt1->val1,…] exports expr with the specified option elements taken to have the specified values.
  • Export["file.xml",{elem1->expr1,elem2->expr2,…},"Rules"] uses rules to specify the elements to be exported.
  • The export format can be explicitly specified in the form Export["file",expr,"ExpressionML"] or Export["file",expr,{"ExpressionML",elems}].
  • See the following reference pages for full general information:
  • Import, Exportimport from or export to a file
    CloudImport, CloudExportimport from or export to a cloud object
    ImportString, ExportStringimport from or export to a string
    ImportByteArray, ExportByteArrayimport from or export to a byte array

Import Elements

  • General Import elements:
  • "Elements" list of elements and options available in this file
    "Summary"summary of the file
    "Rules"list of rules for all available elements
  • Data representation elements:
  • "Boxes"ExpressionML typeset as a Wolfram Language box expression
    "Expression"arbitrary Wolfram Language expression
    "HeldExpression"unevaluated expression
    "XMLObject"ExpressionML as a symbolic XML expression
    "XMLElement"nested XMLElement objects
  • Import and Export use the "Expression" element by default.

Examples

Basic Examples  (1)Summary of the most common use cases

Convert a mathematical expression to the ExpressionML format:

In[1]:=1
✖
https://wolfram.com/xid/0b3t1s6inc-ix6szx
Out[1]=1

Import automatically recognizes the ExpressionML format when reading XML data:

In[2]:=2
✖
https://wolfram.com/xid/0b3t1s6inc-r2wx5u
Out[2]=2

Show the available Import elements:

In[3]:=3
✖
https://wolfram.com/xid/0b3t1s6inc-jt826b
Out[3]=3

Convert ExpressionML to an evaluated expression:

In[4]:=4
✖
https://wolfram.com/xid/0b3t1s6inc-ug6eym
Out[4]=4

Import without evaluating:

In[5]:=5
✖
https://wolfram.com/xid/0b3t1s6inc-1ab8cc
Out[5]=5

Convert ExpressionML to a Wolfram Language typesetting expression:

In[6]:=6
✖
https://wolfram.com/xid/0b3t1s6inc-fofrb5
Out[6]=6

Import ExpressionML to a complete symbolic XML expression:

In[7]:=7
✖
https://wolfram.com/xid/0b3t1s6inc-4vkooh
Out[7]=7

Import ExpressionML to a symbolic XML fragment:

In[8]:=8
✖
https://wolfram.com/xid/0b3t1s6inc-lceikd
Out[8]=8