Table (.dat)

  • Import and Export fully support the tabular data and provide various data conversion and formatting options.
  • Import automatically recognizes common number formats, including C and Fortran notations.
  • Numbers without decimal points are imported as integers.
  • Background

      Generic tabular data.
      Stores numerical and textual information, formatted as a table.
      Supports user-defined field and record separators, field delimiters, currency tokens, and number formats.
      Plain text format.

    Import and Export

    • Import["file.dat"] imports a tabular data file, returning a list of lists.
    • Export["file.dat",expr] exports a two-dimensional array or a Grid to a Table file.
    • Import["file.dat"] returns a two-dimensional array of strings and numbers representing the rows and columns stored in the file.
    • Export["file.dat",array] formats array as rows and columns using the CForm of each element.
    • The Wolfram Language automatically transforms arbitrary expressions to a list of lists when exporting to the "Table" format.
    • Import["file.dat",elem] imports the specified element from a Table file.
    • Import["file.dat",{elem,suba,subb,}] imports a subelement.
    • Import["file.dat",{{elem1,elem2,}}] imports multiple elements.
    • The import format can be specified with Import["file","Table"] or Import["file",{"Table",elem,}].
    • Export["file.dat",expr,elem] creates a Table file by treating expr as specifying element elem.
    • Export["file.dat",{expr1,expr2,},{{elem1,elem2,}}] treats each expri as specifying the corresponding elemi.
    • Export["file.dat",expr,opt1->val1,] exports expr with the specified option elements taken to have the specified values.
    • Export["file.dat",{elem1->expr1,elem2->expr2,},"Rules"] uses rules to specify the elements to be exported.
    • See the reference pages for full general information on Import and Export.
    • ImportString and ExportString support the Table format.

    Notebook Interface

    • Save Selection As exports the selected part of a notebook as a Table file.


    • General Import elements:
    • "Elements"list of elements and options available in this file
      "Rules"full list of rules for each element and option
      "Options"list of rules for options, properties, and settings
    • Data representation elements:
    • "Data"two-dimensional array, representing the rows and columns
      "Grid"table data as a Grid object
    • Import and Export use the "Data" element by default.


    • General Export options:
    • AlignmentNonehow 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.
    • General Import option:
    • CharacterEncoding"ASCII"raw character encoding used in the file
    • Import and Export option:
    • "TextDelimiters"Automaticstring or list of strings used to delimit non-numeric fields
    • By default, Export delimits text fields containing the field separator with double-quote characters.
    • With an explicit setting of "TextDelimiters", Export always uses the specified string tokens to delimit text fields, effectively cycling through the list of delimiters.
    • With "TextDelimiters"->{"<",">"}, Export wraps text fields in angular brackets.
    • Double-quote characters delimiting text fields are not imported by default.
    • Import options:
    • "CurrencyTokens"{{"$", "£", "¥", "€"}, {"c", "¢", "p", "F"}}currency units to be skipped when importing numerical values
      "DateStringFormat"Nonedate format, given as a DateString specification
      "FieldSeparators"{" ","t"}string tokens taken to separate columns
      "IgnoreEmptyLines"Falsewhether to ignore empty lines
      "LineSeparators"{"r\n","n","\r"}string tokens taken to separate rows
      "Numeric"Truewhether to import data fields as numbers if possible
      "NumberPoint""."decimal point string
      "NumberSigns"{"-","+"}strings to use for signs of negative and positive numbers
      "RepeatedSeparators"Truewhether to parse a sequence of field separators as a single separator
      "HeaderLines"0number of lines to skip at the beginning of the file
    • Import converts table entries formatted as specified by the "DateStringFormat" option to a DateObject.
    • Empty lines and lines containing only whitespace characters are converted to an empty list 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.
    • With the default setting for "LineSeparators", Import automatically recognizes all common conventions for the encoding of line-separator characters.
    • Export options:
    • "FieldSeparators""\t"string token used to separate columns
      "TableHeadings"Noneheadings for table columns and rows
    • "TableHeadings" can be set to the following values:
    • Noneno labels
      Automaticgives successive integer labels for columns and rows
      {"col1","col2",}list of column labels
      {rhead,chead}specifies separate labels for the rows and columns
    • Export encodes line separator characters using the convention of the computer system on which the Wolfram Language is being run.


    Basic Examples  (5)

    Export an array of random numbers as a table:

    Click for copyable input

    Export a table formatted as a grid:

    Click for copyable input

    Import the generated file:

    Click for copyable input

    Use ExportString to create a formatted version of an array:

    Click for copyable input

    Import a tabular data file that uses vertical bars as field separators:

    Click for copyable input

    Import converts dates to a Wolfram Language DateObject specification if the date format is specified:

    Click for copyable input

    Create a UTF-8 encoded text file that contains currency tokens:

    Click for copyable input

    When importing this file, currency tokens are automatically skipped:

    Click for copyable input

    The Wolfram Language automatically converts expressions to a list of lists when exporting to the Table format:

    Click for copyable input
    Click for copyable input
    Introduced in 1999
    | Updated in 2014