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Top Forums Shell Programming and Scripting shift and push question in perl Post 302123936 by hankooknara on Wednesday 27th of June 2007 09:36:14 PM
Old 06-27-2007
shift and push question in perl

hi,

another perl question,

I don't understand the below

while (<FILE>) {
push @last5, $_; #add to the end
shift @last5 if @last5 > 5 ; #take from the beginning
}

can someone please explain to me how does

shift @last5 if @last5 > 5 is taking last 5 lines from the file?
I am just not getting it,
1) I thought shift was taking item from begining, shouldn't it be the begining of the file?

2) not understanding how shift @last5 if @last5 > 5 works.. can somone let me know item by item please?

big thank you in advance
 

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XPath::NodeSet(3)					User Contributed Perl Documentation					 XPath::NodeSet(3)

NAME
XML::XPath::NodeSet - a list of XML document nodes DESCRIPTION
An XML::XPath::NodeSet object contains an ordered list of nodes. The nodes each take the same format as described in XML::XPath::XMLParser. SYNOPSIS
my $results = $xp->find('//someelement'); if (!$results->isa('XML::XPath::NodeSet')) { print "Found $results "; exit; } foreach my $context ($results->get_nodelist) { my $newresults = $xp->find('./other/element', $context); ... } API
new() You will almost never have to create a new NodeSet object, as it is all done for you by XPath. get_nodelist() Returns a list of nodes. See XML::XPath::XMLParser for the format of the nodes. string_value() Returns the string-value of the first node in the list. See the XPath specification for what "string-value" means. to_literal() Returns the concatenation of all the string-values of all the nodes in the list. get_node($pos) Returns the node at $pos. The node position in XPath is based at 1, not 0. size() Returns the number of nodes in the NodeSet. pop() Equivalent to perl's pop function. push(@nodes) Equivalent to perl's push function. append($nodeset) Given a nodeset, appends the list of nodes in $nodeset to the end of the current list. shift() Equivalent to perl's shift function. unshift(@nodes) Equivalent to perl's unshift function. prepend($nodeset) Given a nodeset, prepends the list of nodes in $nodeset to the front of the current list. perl v5.16.3 2002-09-02 XPath::NodeSet(3)
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