Variable: org-table-number-regexp

org-table-number-regexp is a customizable variable defined in org-table.el.gz.

Value

"^\\([<>]?[-+^.0-9]*[0-9][-+^.0-9eEdDx()%:]*\\|[<>]?[-+]?0[xX][[:xdigit:].]+\\|[<>]?[-+]?[0-9]+#[0-9a-zA-Z.]+\\|nan\\|[-+u]?inf\\)$"

Documentation

Regular expression for recognizing numbers in table columns.

If a table column contains mostly numbers, it will be aligned to the right. If not, it will be aligned to the left.

The default value of this option is a regular expression which allows anything which looks remotely like a number as used in scientific context. For example, all of the following will be considered a number:
    12 12.2 2.4e-08 2x10^12 4.034+-0.02 2.7(10) >3.5

Other options offered by the customize interface are more restrictive.

Source Code

;; Defined in /usr/src/emacs/lisp/org/org-table.el.gz
(defcustom org-table-number-regexp
  "^\\([<>]?[-+^.0-9]*[0-9][-+^.0-9eEdDx()%:]*\\|[<>]?[-+]?0[xX][[:xdigit:].]+\\|[<>]?[-+]?[0-9]+#[0-9a-zA-Z.]+\\|nan\\|[-+u]?inf\\)$"
  "Regular expression for recognizing numbers in table columns.
If a table column contains mostly numbers, it will be aligned to the
right.  If not, it will be aligned to the left.

The default value of this option is a regular expression which allows
anything which looks remotely like a number as used in scientific
context.  For example, all of the following will be considered a
number:
    12    12.2    2.4e-08    2x10^12    4.034+-0.02    2.7(10)  >3.5

Other options offered by the customize interface are more restrictive."
  :group 'org-table-settings
  :type '(choice
	  (const :tag "Positive Integers"
		 "^[0-9]+$")
	  (const :tag "Integers"
		 "^[-+]?[0-9]+$")
	  (const :tag "Floating Point Numbers"
		 "^[-+]?\\([0-9]*\\.[0-9]+\\|[0-9]+\\.[0-9]*\\)$")
	  (const :tag "Floating Point Number or Integer"
		 "^[-+]?\\([0-9]*\\.[0-9]+\\|[0-9]+\\.?[0-9]*\\)$")
	  (const :tag "Exponential, Floating point, Integer"
		 "^[-+]?[0-9.]+\\([eEdD][-+0-9]+\\)?$")
	  (const :tag "Very General Number-Like, including hex and Calc radix"
		 "^\\([<>]?[-+^.0-9]*[0-9][-+^.0-9eEdDx()%]*\\|[<>]?[-+]?0[xX][[:xdigit:].]+\\|[<>]?[-+]?[0-9]+#[0-9a-zA-Z.]+\\|nan\\|[-+u]?inf\\)$")
	  (const :tag "Very General Number-Like, including hex and Calc radix, allows comma as decimal mark"
		 "^\\([<>]?[-+^.,0-9]*[0-9][-+^.0-9eEdDx()%]*\\|[<>]?[-+]?0[xX][[:xdigit:].]+\\|[<>]?[-+]?[0-9]+#[0-9a-zA-Z.]+\\|nan\\|[-+u]?inf\\)$")
	  (regexp :tag "Regexp:")))