List

• Import and Export provide various data conversion and formatting options for storing lists of numbers or strings.
• Import automatically recognizes common number formats, including C and Fortran notations.
• Numbers without decimal points are imported as integers.

Background & Context

• • Column of numbers or strings.
  • Stores a list of numbers or strings as lines.
  • Plain text format.
  • Is essentially a single-column version of the "Table" format.

Import & Export

• Import["file","List"] imports a text file, returning each line as a string or a number.
• Export["file",list,"List"] writes any list as a column of numbers or strings.
• Import["file","List"] returns a list of strings or numbers, each representing a line of file.
• Export["file",list,"List"] exports list as a column, writing the CForm of each element as a separate line.
• Import["file",{"List",elem} ] imports the specified element from a "List" file.
• Import["file",{"List",elem,sub_a,sub_b,…}] imports a subelement.
• Import["file",{"List",{elem₁,elem₂,…}}] imports multiple elements.
• The format "List" must be explicitly given.
• Export["file",expr, {"List",elem}] creates a "List" file by treating expr as specifying element elem.
• Export["file",{expr₁,expr₂,…},{"List",{elem₁,elem₂,…}}] treats each expr_i as specifying the corresponding elem_i.
• Export["file",expr,"List",opt₁->val₁,…] exports expr with the specified option elements taken to have the specified values.
• Export["file",{elem₁->expr₁,elem₂->expr₂,…},{"List","Rules"}] uses rules to specify the elements to be exported.
• See the following reference pages for full general information:

• 	Import, Export	import from or export to a file
  	CloudImport, CloudExport	import from or export to a cloud object
  	ImportString, ExportString	import from or export to a string
  	ImportByteArray, ExportByteArray	import 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:

• 	"Data"	list of numbers or strings, each representing a line
  	"Grid"	list data as a Grid object

• Import and Export use the "Data" element by default.

Options

• Import and Export option:

• "EmptyField"

  ""

  how to represent empty fields

• Import options:

• 	CharacterEncoding	"ISOLatin1"	raw character encoding used in the file
  	"CurrencyTokens"	{{"$", "", "", ""}, {"c", "", "p", "F"}}	currency units to be skipped when importing numerical values
  	"DateStringFormat"	None	date format, given as a DateString specification
  	"HeaderLines"	0	number of lines to skip at the beginning of the file
  	"IgnoreEmptyLines"	False	whether to ignore empty lines
  	"LineSeparators"	{"∖r\n","∖n","\r"}	string tokens taken to separate list elements
  	"NumberPoint"	"."	string to use for a decimal point
  	"NumberSigns"	{"-","+"}	strings to use for signs of negative and positive numbers
  	"Numeric"	True	whether to import data fields as numbers if possible

• With CharacterEncoding -> Automatic, Import will attempt to infer the character encoding of the file.
• Import converts table entries formatted as specified by the "DateStringFormat" option to a DateList representation of the form {y,m,d,h,m,s}.
• Empty lines and lines containing only whitespace characters are converted to an empty string by default. With "IgnoreEmptyLines" set to True, Import will skip empty lines.
• With "Numeric"->False, numbers will be imported as strings in the form they appear in the file.
• All common conventions for the encoding of newline characters are recognized with the default setting of "LineSeparators".
• General Export options:

• 	Alignment	None	how data is aligned within table columns
  	CharacterEncoding	"UTF8"	raw character encoding used in the file

• Possible settings for Alignment are None, Left, Center, and Right.