PHPで正規表現を使用して日付文字列の位置を取得する方法

Question

php正規表現を使用して次のサンプルの日付文字列の位置を取得する方法は？

たとえば、「2011年12月31日」または「2011年12月31日」の位置を知りたいとします。日付形式は「月日、年」や「月日年」である

<TR> 
<TD VALIGN="top" ALIGN="center"><FONT STYLE="font-family:Times New Roman" SIZE="2"><B>December 31, 2011</B></FONT></TD></TR> 
</TABLE> <P STYLE="margin-top:0px;margin-bottom:0px" ALIGN="center"><FONT STYLE="font-family:Times New Roman" SIZE="1"><B>(Date of Event Which Requires Filing of this Statement) </B></FONT></P> 
<P STYLE="font-size:12px;margin-top:0px;margin-bottom:0px">&nbsp;</P><center> <P STYLE="line-height:6px;margin-top:0px;margin-bottom:2px;border-bottom:1pt solid #000000;width:21%">&nbsp;</P></center> <P STYLE="margin-top:12px;margin-bottom:0px"><FONT 
STYLE="font-family:Times New Roman" SIZE="2"><B>Check the appropriate box to designate the rule pursuant to which this Schedule is filed: </B></FONT></P> <P STYLE="margin-top:12px;margin-bottom:0px; margin-left:8%"><FONT 
STYLE="font-family:Times New Roman" SIZE="2"><B></B><FONT STYLE="FONT-FAMILY:WINGDINGS">&#120;</FONT><B></B><B> Rule 13d-1 (b) </B></FONT></P> <P STYLE="margin-top:12px;margin-bottom:0px; margin-left:8%"><FONT 
STYLE="font-family:Times New Roman" SIZE="2"><B></B><FONT STYLE="FONT-FAMILY:WINGDINGS">&#168;</FONT><B></B><B> Rule 13d-1 (c) </B></FONT></P> <P STYLE="margin-top:12px;margin-bottom:0px; margin-left:8%"><FONT 
STYLE="font-family:Times New Roman" SIZE="2"><B></B><FONT STYLE="FONT-FAMILY:WINGDINGS">&#168;</FONT><B></B><B> Rule 13d-1 (d) </B></FONT></P> <P STYLE="font-size:12px;margin-top:0px;margin-bottom:0px">&nbsp;</P> 
<TABLE STYLE="BORDER-COLLAPSE:COLLAPSE" BORDER="0" CELLPADDING="0" CELLSPACING="0" WIDTH="100%"> 
<TR> 

Answer 1

<?php 
$str = '<TR> 
<TD VALIGN="top" ALIGN="center"><FONT STYLE="font-family:Times New Roman" SIZE="2"><B>December 31, 2011</B></FONT></TD></TR> 
</TABLE> <P STYLE="margin-top:0px;margin-bottom:0px" ALIGN="center"><FONT STYLE="font-family:Times New Roman" SIZE="1"><B>(Date of Event Which Requires Filing of this Statement) </B></FONT></P> 
<P STYLE="font-size:12px;margin-top:0px;margin-bottom:0px">&nbsp;</P><center> <P STYLE="line-height:6px;margin-top:0px;margin-bottom:2px;border-bottom:1pt solid #000000;width:21%">&nbsp;</P></center> <P STYLE="margin-top:12px;margin-bottom:0px"><FONT 
STYLE="font-family:Times New Roman" SIZE="2"><B>Check the appropriate box to designate the rule pursuant to which this Schedule is filed: </B></FONT></P> <P STYLE="margin-top:12px;margin-bottom:0px; margin-left:8%"><FONT 
STYLE="font-family:Times New Roman" SIZE="2"><B></B><FONT STYLE="FONT-FAMILY:WINGDINGS">&#120;</FONT><B></B><B> Rule 13d-1 (b) </B></FONT></P> <P STYLE="margin-top:12px;margin-bottom:0px; margin-left:8%"><FONT 
STYLE="font-family:Times New Roman" SIZE="2"><B></B><FONT STYLE="FONT-FAMILY:WINGDINGS">&#168;</FONT><B></B><B> Rule 13d-1 (c) </B></FONT></P> <P STYLE="margin-top:12px;margin-bottom:0px; margin-left:8%"><FONT 
STYLE="font-family:Times New Roman" SIZE="2"><B></B><FONT STYLE="FONT-FAMILY:WINGDINGS">&#168;</FONT><B></B><B> Rule 13d-1 (d) </B></FONT></P> <P STYLE="font-size:12px;margin-top:0px;margin-bottom:0px">&nbsp;</P> 
<TABLE STYLE="BORDER-COLLAPSE:COLLAPSE" BORDER="0" CELLPADDING="0" CELLSPACING="0" WIDTH="100%"> 
<TR>'; 

$matches = array(); 
preg_match('/(\w+ \d{1,2},? \d{4})/', $str, $matches); // search for date 

$position = strpos($str, $matches[0]); // Find position 
?> 

Answer 2

あなたは必ず正規表現を使用する必要はありません。 PHPの組み込み関数strpos（http://us2.php.net/manual/en/function.strpos.php）は、あなたが渡したものの最初の出現の文字列インデックスを返します。

だからあなたは、月の名前のために、すなわち、何かのような文字列を検索することができます：返信用

<?php 
$mystring = 'abc'; 
$findme = 'a'; 
$pos = strpos($mystring, $findme); 

// Note our use of ===. Simply == would not work as expected 
// because the position of 'a' was the 0th (first) character. 
if ($pos === false) { 
    echo "The string '$findme' was not found in the string '$mystring'"; 
} else { 
    echo "The string '$findme' was found in the string '$mystring'"; 
    echo " and exists at position $pos"; 
} 
?>