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octave: Formatted Output

 
 14.2.4 Formatted Output
 -----------------------
 
 This section describes how to call ‘printf’ and related functions.
 
    The following functions are available for formatted output.  They are
 modeled after the C language functions of the same name, but they
 interpret the format template differently in order to improve the
 performance of printing vector and matrix values.
 
    Implementation Note: For compatibility with MATLAB, escape sequences
 in the template string (e.g., "\n" => newline) are expanded even when
 the template string is defined with single quotes.
 
  -- : printf (TEMPLATE, ...)
      Print optional arguments under the control of the template string
      TEMPLATE to the stream ‘stdout’ and return the number of characters
      printed.
 
      See the Formatted Output section of the GNU Octave manual for a
      complete description of the syntax of the template string.
 
      Implementation Note: For compatibility with MATLAB, escape
      sequences in the template string (e.g., "\n" => newline) are
      expanded even when the template string is defined with single
      quotes.
 
      See also: fprintf XREFfprintf, sprintf XREFsprintf,
      scanf XREFscanf.
 
  -- : fprintf (FID, TEMPLATE, ...)
  -- : fprintf (TEMPLATE, ...)
  -- : NUMBYTES = fprintf (...)
      This function is equivalent to ‘printf’, except that the output is
      written to the file descriptor FID instead of ‘stdout’.
 
      If FID is omitted, the output is written to ‘stdout’ making the
      function exactly equivalent to ‘printf’.
 
      The optional output returns the number of bytes written to the
      file.
 
      Implementation Note: For compatibility with MATLAB, escape
      sequences in the template string (e.g., "\n" => newline) are
      expanded even when the template string is defined with single
      quotes.
 
DONTPRINTYET       See also: fputs XREFfputs, fdisp XREFfdisp, *noteDONTPRINTYET DONTPRINTYET       See also: fputs XREFfputs, fdisp XREFfdisp, 
      fwrite XREFfwrite, fscanf XREFfscanf, *noteprintf:
DONTPRINTYET DONTPRINTYET       See also: fputs XREFfputs, fdisp XREFfdisp, 
      fwrite XREFfwrite, fscanf XREFfscanf, printf

      XREFprintf, sprintf XREFsprintf, fopen XREFfopen.
 
  -- : sprintf (TEMPLATE, ...)
      This is like ‘printf’, except that the output is returned as a
      string.
 
      Unlike the C library function, which requires you to provide a
      suitably sized string as an argument, Octave’s ‘sprintf’ function
      returns the string, automatically sized to hold all of the items
      converted.
 
      Implementation Note: For compatibility with MATLAB, escape
      sequences in the template string (e.g., "\n" => newline) are
      expanded even when the template string is defined with single
      quotes.
 
      See also: printf XREFprintf, fprintf XREFfprintf,
      sscanf XREFsscanf.
 
    The ‘printf’ function can be used to print any number of arguments.
 The template string argument you supply in a call provides information
 not only about the number of additional arguments, but also about their
 types and what style should be used for printing them.
 
    Ordinary characters in the template string are simply written to the
 output stream as-is, while “conversion specifications” introduced by a
 ‘%’ character in the template cause subsequent arguments to be formatted
 and written to the output stream.  For example,
 
      pct = 37;
      filename = "foo.txt";
      printf ("Processed %d%% of '%s'.\nPlease be patient.\n",
              pct, filename);
 
 produces output like
 
      Processed 37% of 'foo.txt'.
      Please be patient.
 
    This example shows the use of the ‘%d’ conversion to specify that a
 scalar argument should be printed in decimal notation, the ‘%s’
 conversion to specify printing of a string argument, and the ‘%%’
 conversion to print a literal ‘%’ character.
 
    There are also conversions for printing an integer argument as an
 unsigned value in octal, decimal, or hexadecimal radix (‘%o’, ‘%u’, or
 ‘%x’, respectively); or as a character value (‘%c’).
 
    Floating-point numbers can be printed in normal, fixed-point notation
 using the ‘%f’ conversion or in exponential notation using the ‘%e’
 conversion.  The ‘%g’ conversion uses either ‘%e’ or ‘%f’ format,
 depending on what is more appropriate for the magnitude of the
 particular number.
 
    You can control formatting more precisely by writing “modifiers”
 between the ‘%’ and the character that indicates which conversion to
 apply.  These slightly alter the ordinary behavior of the conversion.
 For example, most conversion specifications permit you to specify a
 minimum field width and a flag indicating whether you want the result
 left- or right-justified within the field.
 
    The specific flags and modifiers that are permitted and their
 interpretation vary depending on the particular conversion.  They’re all
 described in more detail in the following sections.
 

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