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Programming Portfolio -
Perl
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Written by Jeremy P. McKay
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Tuesday, 14 July 2009 18:23 |
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I have an array called @data. I want to check each element in the array for a value, and if that value exist, I wan to delete it
I could try
@data =~ ~ s/$postalCode//;
### creates an error about private arrays
Maybe this
for my $dat(@data){
$dat=~ s/$postalCode//;
}
The above code does not modify the array at all. We could create a temporary array and then pop puch and reassign upon going through each element. That could be time consumming especially if I have 250,000 arrays. So let's look at map. Charles Galpin has written a pretty simple tutorial on using map here http://articles.techrepublic.com.com/5100-10878_11-1044685.html.
So after reading Charles' article, I try .
map {s/$postalCode//} @data;
Just to a make sure it works I ran the a line of data through it. You should always check yoru code on small sets of data. The test and results are below.
my $data = "Beijing Normal University Beijing 100875 China";
my @data = split/\t/, $data;
$postalCode = 100875;
for my $d(@data){
print "$postalCode $d\n";
}
print "Postal Code Removed\n";
map {s/$postalCode// } @data;
# just checking
for my $d(@data){
print "$postalCode $d\n";
}
exit;
100875 Beijing Normal University
100875 Beijing 100875
100875 China
Postal Code Removed
100875 Beijing Normal University
100875 Beijing
100875 China
Hope this helps in your data munging
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Last Updated ( Tuesday, 14 July 2009 19:19 )
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