.. highlightlang:: us

.. index:: regex

.. _regex:

regex
=====

.. us.tag  regex NOTREADYENGLISH STR New311 Changed570 Changed5140

:ref:`regex` checks if elements of a string vector matches a regular expression.

.. function::  b = regex(ssRegex, svString)
    b = regex(ssRegex, svString, flags)

.. us.return

**Return Value**

*b* is a real vector of size len(svString). *b[i]* contains the vlaue 1 if 
*svString[i]* matches the regular expression and otherwise 0.
.. us.params

**Parameters**

.. uparam:: ssRegex

   *ssRegex* is a scalar string.

.. uparam:: svString

   *ssString* is a string vector.

.. uparam:: flags

   .. list-table::
      :header-rows: 0

      * - REG_ICASE (0x01)
        - 
      * - REG_NEWLINE (0x02)
        - 
      * - REG_NOTBOL (0x04)
        - 
      * - REG_NOTEOL (0x08)
        - 
      * - REG_UTF8 (0x40)
        - 

.. us.example

**Example**

::

   def issym(svSym)
   {
       ssReg = "^[_A-Za-z][_A-Za-z0-9]*$"
       return regex(ssReg, svSym)
   }
   issym(["a", "_a", "1a"])

The following example returns 1 if ssName is the string ``grid`` followed 
by 0 or more numbers, e.g. grid, grid1, grid27:

::

   regex("grid[0-9]*$", ssName);

Returns 1 for integer number, e. g. -1000  or +1287 or 1356:

::

   regex("^[-+]?(\d)*$", ssText)

.. us.history

**History**

.. list-table::
   :header-rows: 1

   * - Version
     - Description
   * - 5.14.0
     - New PCRE version 8.0.
   * - 5.7.0
     - New parameter *flags*.
   * - 3.1.1
     - New

.. us.comment

**Comment**

Regular expression support is provided by the PCRE library package,
which is open source software, written by Philip Hazel, and copyright
by the University of Cambridge, England. Version 8.0. 

License: See :ref:`pcre-license`.

Documentation: See :ref:`regsplit`

.. seealso::
   :ref:`overview-strings`,
   :ref:`regsplit`,
   :ref:`strtok`,
   :ref:`strextract`,
   :ref:`strmatch`,
   :ref:`strmatchi`

:sub:`id-742151`