How to count the Chinese word in a file using regex in perl?

I tried following perl code to count the Chinese word of a file, it seems working but not get the right thing. Any help is greatly appreciated.

The Error message is

Use of uninitialized value $valid in concatenation (.) or string at word_counting.pl line 21, <FILE> line 21.
Total things  = 125, valid words = 

which seems to me the problem is the file format. The "total thing" is 125 that is the string number (125 lines). The strangest part is my console displayed all the individual Chinese words correctly without any problem. The utf-8 pragma is installed.

#!/usr/bin/perl -w
use strict;
use utf8;
use Encode qw(encode);
use Encode::HanExtra;

my $input_file = "sample_file.txt";
my ($total, $valid);
my %count;

open (FILE, "< $input_file") or die "Can't open $input_file: $!";

while (<FILE>) {
 foreach (split) { #break $_ into words, assign each to $_ in turn
 $total++;
 next if /\W|^\d+/;  #strange words skip the remainder of the loop
 $valid++;
 $count{$_}++;  # count each separate word stored in a hash
 ## next comes here ##
      }
   }

   print "Total things  = $total, valid words = $valid\n";
   foreach my $word (sort keys %count) {
      print "$word \t was seen \t $count{$word} \t times.\n";
   }

##---Data----
sample_file.t开发者_StackOverflowxt

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We set STDOUT to the :utf8 IO layer so the says won't show malformed the data, then open the file with the same layer so that the diamond won't read malformed data. Afterward, inside the while, rather than splitting on the empty string, we use a regex with the "East_Asian_Width: Wide" Unicode-like property.

utf8 is for my personal sanity checking, and can be removed (Y).

use strict;
use warnings;
use 5.010;
use utf8;
use autodie;

binmode(STDOUT, ':utf8');

open my $fh, '<:utf8', 'sample_file.txt';

my ($total, $valid);
my %count;

while (<$fh>) {
    $total += length;
    for (/(\p{Ea=W})/g) {
        $valid++;
        $count{$_}++;
    }
}

say "Total things  = $total, valid words = $valid";
for my $word (sort keys %count) {
   say "$word \t was seen \t $count{$word} \t times.";
}

EDIT: J-16 SDiZ and daxim pointed out that the chances of sample_file.txt being in UTF-8 are.. slim. Read their comments, then take a look at the Encode module in perldoc, specifically the 'Encoding via PerlIO' portion.

I may be able to offer some insight, but it's hard to tell if my answer will be "helpful". First, I only speak and read english, so I obviously do not speak or read chinese. I do happen to be the author of RegexKitLite, which is an Objective-C wrapper around the ICU regex engine. This is obviously not perl, :).

Despite this, the ICU regex engine happens to have a feature that sounds remarkably like what it is that you're trying to do. Specifically, the ICU regex engine contains the UREGEX_UWORD modifier option, which can be turned on dynamically via the normal (?w:...) syntax. This modifier performs the following action:

Controls the behavior of \b in a pattern. If set, word boundaries are found according to the definitions of word found in Unicode UAX 29, Text Boundaries. By default, word boundaries are identified by means of a simple classification of characters as either “word” or “non-word”, which approximates traditional regular expression behavior. The results obtained with the two options can be quite different in runs of spaces and other non-word characters.

You can use this in a regex like (?w:\b(.*?)\b) to "extract" words from a string. In the ICU regex engine, it has a fairly powerful "word breaking engine" that is specifically designed to find word breaks in written languages that do not have an explicit space 'character', like english. Again, not reading or writing these languages, my understanding is that "itisroughlysomethinglikethis". The ICU word breaking engine uses heuristics, and occasionally dictionaries, to be able to find the word breaks. It is my understanding that Thai happens to be a particularly difficult case. In fact, I happen to use ฉันกินข้าว (Thai for "I eat rice", or so I was told) with a regex of (?w)\b\s* to perform a split operation on the string to extract the words. Without (?w) you can not split on word breaks. With (?w) it results in the words ฉัน, กิน, and ข้าว.

Provided the above "sounds like the problem you're having", then this could be the reason. If this is the case, then I am not aware of any way to accomplish this in perl, but I wouldn't consider this opinion an authoritative answer since I use the ICU regex engine more often than the perl one and am clearly not properly motivated to find a working perl solution when I've already got one :). Hope this helps.