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macOS Perl matching issue

GeeYouEye

GeeYouEye

macrumors 68000
Original poster
Dec 9, 2001
1,669
10
State of Denial
I have a string $contents, set to $_.

m/^.*/ returns true
m/<table/ returns true.
m/^.*<table/ returns false.

I must be missing something, can anyone tell me what?
 
Can you post the relevant line of your data file and your code. I tried the following:
Code: 
#! /usr/bin/perl

open(HANDLE,"test.html");
@fileContents = <HANDLE>;

if($fileContents[0] =~ m/^.*<table/) {
  print "Matches!\n";
} else {
  print "No match!\n";
}

With a data file:
abx<table>
Click to expand...

Maybe if we can get a peek at your code and data we can help a bit more.

-Lee
 
Code: 
#!/usr/bin/perl -w

open HANDLE, "test.jsp";
@fileContents = <HANDLE>;
$contents = join("", @fileContents);
$_ = $contents;
if(m/^.*<table/) {
  print "Matches!\n";
} else {
  print "No match!\n";
}

And the contents of test.jsp are:

Code: 
<%@ page language="java" import="java.util.*, java.io.*, java.text.*"%>
<jsp:useBean id="cart" scope="session" class="com.chengdesign.Cart2" />
<jsp:useBean id="members" scope="session" class="com.chengdesign.Members" />
<jsp:useBean id="template" scope="page" class="com.concreteexchange.CETemplate" />
<%
if( request.getServerPort() == 443 ) {
    response.sendRedirect( "http://" + template.getBaseDomain() + request.getRequestURI() );
    return;
};

try {
/********************
* Member Access Control Logic
* Throws ServletException, IOException
* NOT_ALLOWED_URI: Optional. Adding this parameter, typically the login page, would force a non member to that URI for further action.
* TERMS_URI: Optional. Adding this parameter, typically the terms page, would force a member that has not accepted the terms to that URI for further action. Leave blank for TERMS Page ONLY.
********************* 
* members.directMemberAccess( REQUEST_OBJECT, RESPONSE_OBJECT, [NOT_ALLOWED_URI], [TERMS_URI] );
********************/
	if( members.directMemberAccess( request, response, "", "https://" + template.getBaseDomain() + template.getBaseDirectory() + "member_terms.jsp?uri=" + request.getRequestURI() ) ) {
		return; // End JSP Page if page has been redirected (TRUE)
	};
} catch ( Exception ex ) {
	response.sendRedirect( "http://" + template.getBaseDomain() + template.getBaseDirectory() ); // Something Bad Happend Redirect to Home Page
	return;
};

/********************
* Template/Page Navigation Setup
* Valid Range is 0 - Max Count
* 0 = None Selected
********************* 
* template.setHeaderProperties( PRIMARY_NAV_ID, SECONDARY_NAV_ID, MEMBERS_LEVEL );
********************/
template.setHeaderProperties( 6, 5, members.getLevel() );

%><html>
<head>
   <title>Decorative Concrete Article in Pure Contemporary Magazine</title>
	<meta name="description" content="Decorative concrete and its many uses inside the home - for floors, walls, fireplaces. Mix properties, pouring techniques and finishes. An article from Decorative Concrete, October/November 2005">										
   	<meta name="keywords" content="concrete countertops, kitchen, bathroom">						
    <link rel="stylesheet" type="text/css" href="<%= template.getBaseDirectory() %>css/style.css" title="master">
    <link rel="stylesheet" type="text/css" href="<%= template.getBaseDirectory() %>css/style_additional.css">
	<script language="JavaScript" src="<%= template.getBaseDirectory() %>js/core.js"></script>
    <script language="JavaScript">
        <!--
        // Define PreLoad Image List
        var preLoadList = new Array;
        var preLoadListCount = 0;
        preLoadList[preLoadListCount++] = "<%= template.getBaseDirectory() %>images/top_cd_visit_m.gif";
        preLoadList[preLoadListCount++] = "<%= template.getBaseDirectory() %>images/secnav_login_m.gif";

        //NAV CODE BASE
        preloadImages();
        dqm__codebase = "<%= template.getBaseDirectory() %>js/";
        // -->
    </script>
</head>
<body bgcolor="#5f6669" bottommargin="0" topmargin="0" leftmargin="0" rightmargin="0" marginheight="0" marginwidth="0">
<div align="center"><%= template.getPageHeaderHTML() %>
<%= template.getPrimaryNavJS() %>
<script language="JavaScript1.2" src="<%= template.getBaseDirectory() %>js/dqm_loader.js"></script>
<%= template.getPrimaryNavHTML() %>
<%= template.getSecondaryNavHTML() %>
<table width="800" border="0" cellspacing="0" cellpadding="0">
...

I'm trying to strip the everything but the content table from the top of the file (I'll handle the bottom later), and replace it with a new set of headers and includes, but I reduced it to this matching problem to eliminate the possibility that the other half of the s/// was the culprit.
 
You need to turn on multiline mode, using an m after the second slash in your regex.
Code: 
#!/usr/bin/perl -w

open HANDLE, "test.jsp";
@fileContents = <HANDLE>;
$contents = join("", @fileContents);
$_ = $contents;
if(m/^.*<table/m) {
  print "Matches!\n";
} else {
  print "No match!\n";
}

Otherwise the anchors are specific to the start and end of the whole string. Note that I did not know this at all when starting to look at this, but i started to notice that if i put something instead of table that matched on the first line, it worked, and started poking around.

-Lee
 
Well crud, now it doesn't work in a substitution. I tried

s/^.*<table/$header/m and
s/\A.*<table/$header/.
Neither worked.

EDIT: n/m that was related to something else. Ignore.
 
Only use regex's when you don't know what you are looking for. When you do know what you are looking for a substr/index is usually quicker.

Code: 
my $content;

{
 open HANDLE, "test.jsp" or die "aaaargh!: $!";
 local $/ = undef;
 $content = <HANDLE>;
 close HANDLE
};

my $table = substr($content,index($content,'<table '));

print "Using substr:\n$table\n";

# '?' is important here, .* is greedy. Without '?' your code would break on pages with multiple tables.
$content =~s/.*?<table//s;

print "With substitute: \n$content\n";

prints:

Code: 
Using substr:
<table width="800" border="0" cellspacing="0" cellpadding="0">
...

With substitute:
 width="800" border="0" cellspacing="0" cellpadding="0">
...
 
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