Regular Expressions 101

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An explanation of your regex will be automatically generated as you type.
Detailed match information will be displayed here automatically.
  • All Tokens
  • Common Tokens
  • General Tokens
  • Anchors
  • Meta Sequences
  • Quantifiers
  • Group Constructs
  • Character Classes
  • Flags/Modifiers
  • Substitution
  • A single character of: a, b or c
    [abc]
  • A character except: a, b or c
    [^abc]
  • A character in the range: a-z
    [a-z]
  • A character not in the range: a-z
    [^a-z]
  • A character in the range: a-z or A-Z
    [a-zA-Z]
  • Any single character
    .
  • Alternate - match either a or b
    a|b
  • Any whitespace character
    \s
  • Any non-whitespace character
    \S
  • Any digit
    \d
  • Any non-digit
    \D
  • Any word character
    \w
  • Any non-word character
    \W
  • Non-capturing group
    (?:...)
  • Capturing group
    (...)
  • Zero or one of a
    a?
  • Zero or more of a
    a*
  • One or more of a
    a+
  • Exactly 3 of a
    a{3}
  • 3 or more of a
    a{3,}
  • Between 3 and 6 of a
    a{3,6}
  • Start of string
    ^
  • End of string
    $
  • A word boundary
    \b
  • Non-word boundary
    \B

Regular Expression

/
/
s

Test String

Code Generator

Generated Code

$re = '/port\s*\((.*?)(?:\)\s*;\s*\w)/s'; $str = 'entity pci_bfm is generic ( G_INST_NAME : string := "PCI_BFM"; G_HANDLE_NO : rpciBfmHandleNo := 0; G_IDSEL_POS_EXT_TARGET : idsel_pos := 30; G_IDSEL_POS_INT_TARGET : idsel_pos := 29 ) ; port( i_tb_stop : in boolean; -- Testbench global sto o_clk : out std_logic; -- PCI clock. o_rstn : out std_logic; -- PCI reset. o_idsel : out std_logic; -- Initialization devic i_reqn : in std_logic; -- Request. The reqn in o_gntn : out std_logic; -- Grant. The gntn onpu io_ad : inout std_logic_vector(31 downto 0); -- Address/data bus. Th io_cben : inout std_logic_vector(3 downto 0); -- Command/byte enable. io_par : inout std_logic; -- Parity. The par sign io_framen : inout std_logic; -- Frame. The framen si io_irdyn : inout std_logic; -- Initiator ready. The io_devseln : inout std_logic; -- Device select. Targe io_trdyn : inout std_logic; -- Target ready. The tr io_stopn : inout std_logic; -- Stop. The stopn sign io_perrn : inout std_logic; -- Parity error. The pe i_serrn : in std_logic; -- System error. The se i_intan : in std_logic; -- Interrupt A. The int o_lockn : out std_logic -- Locked operations. R ) ; generic ( G_INST_NAME : string := "PCI_BFM"; G_HANDLE_NO : rpciBfmHandleNo := 0; G_IDSEL_POS_EXT_TARGET : idsel_pos := 30; G_IDSEL_POS_INT_TARGET : idsel_pos := 29 ) ; end entity pci_bfm;'; preg_match($re, $str, $matches, PREG_OFFSET_CAPTURE, 0); // Print the entire match result var_dump($matches);

Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for PHP, please visit: http://php.net/manual/en/ref.pcre.php